[workflow] added docker latest tag for release (#3920)

.github/workflows/release_docker_after_publish.yml

@@ -23,8 +23,11 @@ jobs:
         run: |
           version=$(cat version.txt)
           tag=hpcaitech/colossalai:$version
+          latest=hpcaitech/colossalai:latest
           docker build --build-arg http_proxy=http://172.17.0.1:7890 --build-arg https_proxy=http://172.17.0.1:7890 --build-arg VERSION=v${version} -t $tag ./docker
+          docker tag $tag $latest
           echo "tag=${tag}" >> $GITHUB_OUTPUT
+          echo "latest=${latest}" >> $GITHUB_OUTPUT
 
       - name: Log in to Docker Hub
         uses: docker/login-action@f054a8b539a109f9f41c372932f1ae047eff08c9
@@ -36,6 +39,7 @@ jobs:
         id: docker-push
         run: |
           docker push ${{ steps.build.outputs.tag }}
+          docker push ${{ steps.build.outputs.latest }}
 
   notify:
     name: Notify Lark via webhook