Packit: constrain downstream koji job to fedora package

This constraint helps to avoid duplicate Packit jobs. The effect will
only be seen at the time of Fedora koji build and not on upstream. This
doesn't affect upstream.

Signed-off-by: Lokesh Mandvekar <lsm5@fedoraproject.org>

.packit.yaml

@@ -107,6 +107,7 @@ jobs:
   # Fedora Koji build
   - job: koji_build
     trigger: commit
+    packages: [skopeo-fedora]
     sidetag_group: podman-releases
     # Dependents are not rpm dependencies, but the package whose bodhi update
     # should include this package.