Get the image tag from supplied ref

We need to pass the ref used in the workflow. If we supply a tag,
we should just get that same tag. If we supply a branch, we should
get the latest release from that branch.

Signed-off-by: Gabriel Adrian Samfira <gsamfira@cloudbasesolutions.com>

.github/workflows/build-and-push.yml

@@ -48,7 +48,7 @@ jobs:
             if [ "$GH_REF" == "main" ]; then
               IMAGE_TAG="nightly"
             else
-              IMAGE_TAG=$(git describe --tags --match='v[0-9]*' --always)
+              IMAGE_TAG=$(git describe --tags --match='v[0-9]*' --always ${GH_REF})
             fi
             docker buildx build \
               --provenance=false \