GHA: Only run GHA comment script if PR origin is from FINOS - v2

Changing the variable used to check the source repo of a PR

Author: kriswest

.github/workflows/coverage.yml

@@ -53,7 +53,7 @@ jobs:
 
     # Only post comments if the PR came from FINOS (the only repo with permission to run it)
     - name: PR comment with file
-      if: github.repository == 'finos/FDC3'
+      if: github.event.pull_request.head.repo.full_name == 'finos/FDC3'
       uses: thollander/actions-comment-pull-request@v3
       with:
         file-path: test-summary.md