docker: add {VERSION}-slim tag to releases (#1977)

.github/workflows/release_publish_docker-image.yml

@@ -30,7 +30,7 @@ jobs:
           TAGS_SLIM="${DOCKER_IMAGE}:${VERSION}-slim"
           if [[ ${{ github.event.action }} == released ]]; then
             TAGS=$TAGS,${DOCKER_IMAGE}:latest,${GHCR_IMAGE}:latest
-            TAGS_SLIM=$TAGS,${DOCKER_IMAGE}:slim
+            TAGS_SLIM=$TAGS_SLIM,${DOCKER_IMAGE}:slim
           fi
           echo ::set-output name=version::${VERSION}
           echo ::set-output name=tags::${TAGS}