ci: bump docker/build-push-action from 6.17.0 to 6.18.0

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 6.17.0 to 6.18.0.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](1dc7386353...263435318d)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-version: 6.18.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/build-xemu-win64-toolchain.yml

@@ -44,7 +44,7 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
       - name: Build and push image
-        uses: docker/build-push-action@1dc73863535b631f98b2378be8619f83b136f4a0 # v5
+        uses: docker/build-push-action@263435318d21b8e681c14492fe198d362a7d2c83 # v5
         with:
           context: ubuntu-win64-cross
           push: ${{ github.event_name == 'push' && github.ref == 'refs/heads/master' }}