Docker publish : add meta action for auto tag management

.github/workflows/docker-release.yml

@@ -12,6 +12,12 @@ jobs:
     steps:
       - name: Check out the repo
         uses: actions/checkout@v2
+      - name: Docker meta
+        id: docker_meta
+        uses: crazy-max/ghaction-docker-meta@v1
+        with:
+          images: camptocamp/cups_exporter
+          tag-semver: {{version}}
       - name: Push to GitHub Packages
         uses: docker/build-push-action@v2
         with:
@@ -19,6 +25,4 @@ jobs:
           password: ${{ secrets.PAT }}
           registry: ghcr.io
           push: true
-          tags: |
-            camptocamp/cups_exporter:latest
-            camptocamp/cups_exporter:${{ github.event.release.tag_name }}
+          tags: ${{ steps.docker_meta.outputs.tags }}