Fix use of .env tag in metadata step

Author: mcduffie

.github/workflows/docker-publish.yml

@@ -106,7 +106,7 @@ jobs:
           tags: |
             type=ref,event=branch
             type=ref,event=tag
-            type=semver,pattern={{version}},value=${{ steps.dotenv.outputs.docker_tag }}
+            type=semver,pattern={{version}},value=${{ env.DOCKER_TAG }}
 
       # Build and push Docker image with Buildx (don't push on PR)
       # https://github.com/docker/build-push-action