Update GitHub Actions to trigger on PR events

- Added explicit PR event types: opened, synchronize, reopened
- Ensures checks run when PRs are created or updated

Author: simbo1905

.github/workflows/maven.yml

@@ -5,6 +5,7 @@ on:
     branches: [ "main" ]
   pull_request:
     branches: [ "main" ]
+    types: [opened, synchronize, reopened]
 
 jobs:
   build: