gating.yaml: Add RHEL rule

That allows us to keep the package in sync between Fedora and CentOS
Stream.

gating.yaml

@@ -4,3 +4,11 @@ product_versions:
 decision_context: bodhi_update_push_stable
 rules:
   - !PassingTestCaseRule {test_case_name: fedora-ci.koji-build.tier0.functional}
+
+--- !Policy
+product_versions:
+  - rhel-8
+  - rhel-9
+decision_context: osci_compose_gate
+rules:
+  - !PassingTestCaseRule {test_case_name: osci.brew-build.tier0.functional}