extract metadata for docker images from git

Author: Ivan Rylach

.github/workflows/release.yml

@@ -13,10 +13,14 @@ jobs:
     steps:
       - name: Check out
         uses: actions/checkout@v2
-      - name: Set environment variables
-        run: echo "RELEASE_VERSION=${GITHUB_REF#refs/*/}" >> $GITHUB_ENV
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v3
+        with:
+          images: checkr/idempotent-request-server
       - name: Build the Docker image
         uses: docker/build-push-action@v2
         with:
-          tags: idempotent-requests-server:$RELEASE_VERSION
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
           push: false