Add statuses: write permission for pull_request trigger

Author: naushir

.github/workflows/camera-test-libpisp.yml

@@ -6,6 +6,9 @@ on:
   pull_request:
     branches: [main]
 
+permissions:
+  statuses: write
+
 jobs:
   trigger-camera-tests:
     runs-on: [self-hosted, camera-test-bridge]