ci: removing clirr from required checks (#110)

Making CLIRR not required. The version bumps are now controlled by the Release Please and OwlBot. The CL authors create appropriate change description to control major version bumps.

Author: suztomo

.github/sync-repo-settings.yaml

@@ -32,7 +32,6 @@ branchProtectionRules:
   - "dependencies (8)"
   - "dependencies (11)"
   - "lint"
-  - "clirr"
   - "units (8)"
   - "units (11)"
   - "Kokoro - Test: Integration"