limit /ci diff to members only

Author: Emilgardis

.github/workflows/diff.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     outputs:
       diffs: ${{ steps.regress-ci.outputs.diffs }}
-    if: github.event.issue.pull_request && (contains(github.event.comment.body, '\n/ci') || startsWith(github.event.comment.body, '/ci'))
+    if: github.event.issue.pull_request && github.event.comment.author_association == 'MEMBER' && (contains(github.event.comment.body, '\n/ci') || startsWith(github.event.comment.body, '/ci'))
     steps:
       - uses: actions/checkout@v4