Update cla.yml

Author: hamzaremmal

.github/workflows/cla.yml

@@ -3,7 +3,7 @@ on:
   # This is a temporary trigger to cover already opened PRs
   workflow_dispatch:
   pull_request:
-    types: [opened, synchronize]
+    types: opened
     branches-ignore:
       - 'language-reference-stable'