GHA: Fix cirrus re-run workflow for other repos.

The checkout action by default, clones the current repository.  However,
since this workflow is re-used by other repos, and it calls scripts in
the podman repo, those calls will all fail.  Fix this by hard-coding the
podman repo.

Ref: https://github.com/actions/checkout

Signed-off-by: Chris Evich <cevich@redhat.com>

.github/workflows/rerun_cirrus_cron.yml

@@ -44,6 +44,9 @@ jobs:
         steps:
             - uses: actions/checkout@v3
               with:
+                  # All scripts used by this workflow live in podman repo.
+                  repository: "containers/podman"
+                  ref: "main"
                   persist-credentials: false
 
             - name: Get failed cron names and Build IDs