chore(ci): update of CLA workflow

Removed `synchronize` and `closed` types of pull_request_target trigger

Author: web-flow

.github/workflows/cla.yaml

@@ -4,7 +4,7 @@ on:
   issue_comment:
     types: [created]
   pull_request_target:
-    types: [opened, closed, synchronize]
+    types: [opened]
 
 permissions:
   contents: read