chore: update repo semaphore project

Author: ConfluentJenkins

.semaphore/project.yml

@@ -17,6 +17,11 @@ spec:
       pipeline_files:
       - path: .semaphore/semaphore.yml
         level: pipeline
+    whitelist:
+      branches:
+      - master
+      - main
+      - /^v\d+\.\d+\.x$/
   custom_permissions: true
   debug_permissions:
   - empty