ci: Try to push to ghcr.io (#2051)

I don't think I can change where it's pushed and start using it in the
same PR, so will try to first update the push part, and then change
where the image is used. Only doing it for CI image to not break
anything.

.github/workflows/update_docker_ci.yml

@@ -1,4 +1,5 @@
 name: Update CI docker image
+
 on:
   pull_request:
     paths:
@@ -29,7 +30,10 @@ jobs:
           DOCKERHUB_PW: ${{ secrets.DOCKERHUB_PW }}
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         with:
-          image_name: rippleci/clio_ci
+          images: |
+            rippleci/clio_ci
+            ghcr.io/xrplf/clio-ci
+          dockerhub_repo: rippleci/clio_ci
           push_image: ${{ github.event_name != 'pull_request' }}
           directory: docker/ci
           tags: |