ci: modify image tagging behavior

push to 'main' updates 'latest' and SHA tag
push to 'rhoai-v*' updates 'rhoai-v*-latest' and SHA tag
push elsewhere updates just SHA tag

Signed-off-by: Nathan Weinberg <nweinber@redhat.com>

Author: nathan-weinberg

.github/workflows/redhat-distro-container.yml

@@ -137,6 +137,6 @@ jobs:
           file: distribution/Containerfile
           platforms: ${{ matrix.platform }}
           push: true
-          tags: ${{ env.IMAGE_NAME }}:${{ github.sha }}${{ github.ref == 'refs/heads/main' && format(',{0}:latest', env.IMAGE_NAME) || '' }}  # only update 'latest' tag if push is to the 'main' branch
+          tags: ${{ env.IMAGE_NAME }}:${{ github.sha }}${{ github.ref == 'refs/heads/main' && format(',{0}:latest', env.IMAGE_NAME) || (startsWith(github.ref, 'refs/heads/rhoai-v') && format(',{0}:{1}-latest', env.IMAGE_NAME, github.ref_name)) || '' }}  # update 'latest' on main, '<branch-name>-latest' on rhoai-v* branches
           cache-from: type=gha
           cache-to: type=gha,mode=max