ci(repo): pull using action

.github/workflows/repo-push.yaml

@@ -20,13 +20,12 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
           registry: docker.pkg.github.com
-      - name: Pull existing
-        run: docker pull docker.pkg.github.com/engineer-man/piston/repo-builder
 
       - name: Build and push repo
         uses: docker/build-push-action@v2
         with:
           context: repo
+          pull: true
           push: true
           tags: |
             docker.pkg.github.com/engineer-man/piston/repo-builder