ci: use git describe for OCI image version label

Author: buchdag

.github/workflows/dockerhub.yml

@@ -29,6 +29,9 @@ jobs:
         uses: actions/checkout@v2
         with:
           fetch-depth: 0
+      
+      - name: Retrieve version
+        run: echo "GIT_DESCRIBE=$(git describe --tags)" >> $GITHUB_ENV
 
       - name: Get Docker tags for Alpine based image
         if: ${{ matrix.base == 'alpine' }}
@@ -42,6 +45,8 @@ jobs:
             type=semver,pattern={{version}}
             type=semver,pattern={{major}}.{{minor}}
             type=raw,value=latest,enable=${{ endsWith(github.ref, github.event.repository.default_branch) }}
+          labels: |
+            org.opencontainers.image.version=${{ env.GIT_DESCRIBE }}
       
       - name: Get Docker tags for Debian based image
         if: ${{ matrix.base == 'debian' }}
@@ -55,11 +60,10 @@ jobs:
             type=semver,suffix=-debian,pattern={{version}}
             type=semver,suffix=-debian,pattern={{major}}.{{minor}}
             type=raw,value=debian,enable=${{ endsWith(github.ref, github.event.repository.default_branch) }}
+          labels: |
+            org.opencontainers.image.version=${{ env.GIT_DESCRIBE }}
           flavor: latest=false
 
-      - name: Retrieve version
-        run: echo "VERSION=$(git describe --tags)" >> $GITHUB_ENV
-
       - name: Set up QEMU
         uses: docker/setup-qemu-action@v1
 
@@ -77,7 +81,7 @@ jobs:
         id: docker_build_alpine
         uses: docker/build-push-action@v2
         with:
-          build-args: VERSION=${{ env.VERSION }}
+          build-args: VERSION=${{ env.GIT_DESCRIBE }}
           platforms: linux/amd64,linux/arm64,linux/arm/v7
           push: true
           tags: ${{ steps.docker_meta_alpine.outputs.tags }}
@@ -88,7 +92,7 @@ jobs:
         id: docker_build_debian
         uses: docker/build-push-action@v2
         with:
-          build-args: VERSION=${{ env.VERSION }}
+          build-args: VERSION=${{ env.GIT_DESCRIBE }}
           file: Dockerfile.debian
           platforms: linux/amd64,linux/arm64,linux/arm/v7
           push: true