cmake: Check UPDATE_APPCAST before TAG_RELEASE.

Check for UPDATE_APPCAST being set before checking for TAG_RELEASE, as
the UPDATE_APPCAST script may be run in the same build directory where
TAG_RELEASE was just run.

Signed-off-by: Rafael Kitover <rkitover@gmail.com>

CMakeLists.txt

@@ -17,14 +17,14 @@ endif()
 
 set(CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake)
 
-if(TAG_RELEASE)
-    include(MakeReleaseCommitAndTag)
-endif()
-
 if(UPDATE_APPCAST)
     include(UpdateAppcast)
 endif()
 
+if(TAG_RELEASE)
+    include(MakeReleaseCommitAndTag)
+endif()
+
 set(VCPKG_DEPS zlib libpng SDL2 SFML gettext wxWidgets)
 
 # appveyor job goes over time limit if building ffmpeg during initial cache