Add multiple tags to the docker image, then push

.github/workflows/docker-hub-build-push.yml

@@ -11,6 +11,8 @@ jobs:
     steps:
       - name: checkout code
         uses: actions/checkout@v2
+      - name: extract tag string
+        run: echo "RELEASE_VERSION=${GITHUB_REF#refs/*/}" >> $GITHUB_ENV
       - name: install buildx
         id: buildx
         uses: crazy-max/ghaction-docker-buildx@v1
@@ -18,8 +20,9 @@ jobs:
           version: latest
       - name: login to docker hub
         run: echo "${{ secrets.DOCKER_PASSWORD }}" | docker login -u "${{ secrets.DOCKER_USERNAME }}" --password-stdin
-      - name: build the image
+      - name: build and push the image
         run: |
           docker buildx build --push \
             --tag shizunge/endlessh-go:latest \
+            --tag shizunge/endlessh-go:$RELEASE_VERSION \
             --platform linux/amd64,linux/arm/v7,linux/arm64 .