ci: use git describe for OCI image version label

Author: buchdag

.github/workflows/dockerhub.yml

@@ -27,6 +27,9 @@ 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
         id: docker_meta
@@ -39,6 +42,8 @@ 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: Set up QEMU
         uses: docker/setup-qemu-action@v1
@@ -52,9 +57,6 @@ jobs:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
 
-      - name: Retrieve version
-        run: echo "GIT_DESCRIBE=$(git describe --tags)" >> $GITHUB_ENV
-      
       - name: Build and push
         id: docker_build
         uses: docker/build-push-action@v2