Pull rawhide image from quay.io instead of the Docker registry

The quay.io image is updated from every successful rawhide compose,
whereas the Docker registry is less frequent. We are seeing issues
because we are out of sync with latest rawhide (the dnf/dnf5 revert) and
this shoudl give us some immunity to that in the future.

.github/workflows/build-tests.yml

@@ -159,7 +159,8 @@ jobs:
   sandbox-test:
     name: Sandbox Test
     runs-on: ubuntu-latest
-    container: fedora:rawhide
+    container:
+      image: quay.io/fedora/fedora:rawhide
     steps:
     - name: Clone repository
       uses: actions/checkout@v3