Fix PR submitter detection (#342)

.github/workflows/require-changelog-for-PRs.yml

@@ -10,14 +10,22 @@ jobs:
     # allow dependabot PRs to have no changelog
     if: github.actor != 'dependabot[bot]'
     env:
-      PR_SUBMITTER: ${{ github.actor }}
       PR_NUMBER: ${{ github.event.number }}
       PR_BASE: ${{ github.base_ref }}
     steps:
       - uses: actions/checkout@v4
+
       - name: Fetch PR base
         run: git fetch --no-tags --prune --depth=1 origin
+
+      # cannot use `github.actor`: the triggering commit may be authored by a maintainer
+      - name: Get PR submitter
+        id: get-submitter
+        run: curl -sSfL https://api.github.com/repos/sharkdp/bat/pulls/${PR_NUMBER} | jq -r '"submitter=" + .user.login' | tee -a $GITHUB_OUTPUT
+
       - name: Search for added line in changelog
+        env:
+          PR_SUBMITTER: ${{ steps.get-submitter.outputs.submitter }}
         run: |
           ADDED=$(git diff -U0 "origin/${PR_BASE}" HEAD -- CHANGELOG.md | grep -P '^\+[^\+].+$')
           echo "Added lines in CHANGELOG.md:"