gitlab-ci: Replace YAML anchors by extends (container_job)

'extends' is an alternative to using YAML anchors
and is a little more flexible and readable. See:
https://docs.gitlab.com/ee/ci/yaml/#extends

Reviewed-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20210418233448.1267991-2-f4bug@amsat.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>

.gitlab-ci.d/containers.yml

@@ -1,4 +1,4 @@
-.container_job_template: &container_job_definition
+.container_job_template:
   image: docker:stable
   stage: containers
   services:
@@ -22,230 +22,230 @@
     - docker logout
 
 amd64-alpine-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: alpine
 
 amd64-centos7-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: centos7
 
 amd64-centos8-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: centos8
 
 amd64-debian10-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: debian10
 
 amd64-debian11-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: debian11
 
 alpha-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-alpha-cross
 
 amd64-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-amd64-cross
 
 amd64-debian-user-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-all-test-cross
 
 amd64-debian-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-amd64
 
 arm64-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-arm64-cross
 
 arm64-test-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian11-container']
   variables:
     NAME: debian-arm64-test-cross
 
 armel-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-armel-cross
 
 armhf-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-armhf-cross
 
 hppa-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-hppa-cross
 
 m68k-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-m68k-cross
 
 mips64-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-mips64-cross
 
 mips64el-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-mips64el-cross
 
 mips-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-mips-cross
 
 mipsel-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-mipsel-cross
 
 powerpc-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-powerpc-cross
 
 ppc64-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-ppc64-cross
 
 ppc64el-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-ppc64el-cross
 
 riscv64-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-riscv64-cross
 
 s390x-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-s390x-cross
 
 sh4-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-sh4-cross
 
 sparc64-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-sparc64-cross
 
 tricore-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   stage: containers-layer2
   needs: ['amd64-debian10-container']
   variables:
     NAME: debian-tricore-cross
 
 xtensa-debian-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: debian-xtensa-cross
 
 cris-fedora-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: fedora-cris-cross
 
 amd64-fedora-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: fedora
 
 i386-fedora-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: fedora-i386-cross
 
 win32-fedora-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: fedora-win32-cross
 
 win64-fedora-cross-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: fedora-win64-cross
 
 amd64-ubuntu1804-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: ubuntu1804
 
 amd64-ubuntu2004-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: ubuntu2004
 
 amd64-ubuntu-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: ubuntu
 
 amd64-opensuse-leap-container:
-  <<: *container_job_definition
+  extends: .container_job_template
   variables:
     NAME: opensuse-leap