Update gh action

.github/workflows/dockerimage.yml

@@ -3,20 +3,13 @@ name: Docker Image CI
 on: [push]
 
 jobs:
-
   build:
-
     runs-on: ubuntu-latest
-
     steps:
     - uses: actions/checkout@v1
-    - name: Get image tag
-      shell: bash
-      run: echo "##[set-output name=tag;]$(if [ ${GITHUB_REF#refs/heads/} = 'master' ]; then echo 'latest'; else echo ${GITHUB_REF#refs/heads/}; fi)"
-      id: set_tag
-    - uses: jerray/publish-docker-action@master
+    - uses: docker/build-push-action@v1
       with:
         username: ${{ secrets.DOCKER_USER }}
         password: ${{ secrets.DOCKER_PWD }}
         repository: elleflorio/svn-server
-        tags: ${{ steps.set_tag.outputs.tag }}
+        tag_with_ref: true