Try to fix publishing action (#111)

Author: pepakriz

.github/workflows/release-image.yml

@@ -11,12 +11,15 @@ jobs:
     steps:
       - uses: actions/checkout@v2
 
+      - name: Get release version
+        id: get_version
+        run: echo "RELEASE_VERSION=$(echo ${GITHUB_REF:10})" >> $GITHUB_ENV
+
       - name: Publish to Registry
-        pre: echo ::save-state name=RELEASE_VERSION::$(echo ${GITHUB_REF:10})
         uses: elgohr/Publish-Docker-Github-Action@master
         with:
           name: pepakriz/gitlab-merger-bot
           username: ${{ secrets.DOCKER_USERNAME }}
           password: ${{ secrets.DOCKER_PASSWORD }}
           tag_semver: true
-          tags: "latest,${{ env.STATE_RELEASE_VERSION }}"
+          tags: "latest,${{ env.RELEASE_VERSION }}"