.github/workflows/cla.yml: Re-run CLA Assistant when contributors sign

Trigger cla.yml on new comments and run the action only for PR comments
containing the signature text or recheck. Existing CLA checks on pull request
events remain unchanged.

Author: JorjMcKie

.github/workflows/cla.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: "CLA Assistant"
-        if: (github.event.comment.body == 'recheck' || github.event.comment.body == 'I have read the CLA Document and I hereby sign the CLA') || github.event_name == 'pull_request_target'
+        if: github.event_name == 'pull_request_target' || (github.event.issue.pull_request && (github.event.comment.body == 'recheck' || github.event.comment.body == 'I have read the CLA Document and I hereby sign the CLA'))
         # Beta Release
         uses: contributor-assistant/github-action@v2.4.0
         env: