Publish test image (#1185)

* push image on PR

* add docker login in CI

* publish image once PR is merged

* update order

* change condition when publish image

* add image publish as a separate github action

* remove condition

* set go env

.github/workflows/image.yaml

@@ -7,6 +7,17 @@ jobs:
   push-images:
     runs-on: ubuntu-latest
     steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Unshallow
+        run: git fetch --prune --unshallow
+
+      - name: Set up Go
+        uses: actions/setup-go@v2
+        with:
+          go-version: 1.14
+          
       - name: login to docker hub
         run: echo "${{ secrets.DOCKERIO_PASSWORD }}" | docker login -u "${{ secrets.DOCKERIO_USERNAME }}" --password-stdin