fix branch issue

Author: Blargian

.github/workflows/trademark-cla-approval.yml

@@ -141,7 +141,7 @@ jobs:
             core.setOutput('pr_number', prNumber);
             core.setOutput('pr_author', prAuthor);
             core.setOutput('approved_by', prAuthor);
-            core.setOutput('pr_head_sha', pr.head.sha);
+            core.setOutput('pr_head_ref', pr.head.ref);
             
             // Add confirmation comment
             const confirmationBody = [
@@ -170,8 +170,8 @@ jobs:
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
-          # For issue_comment events, checkout the PR head
-          ref: ${{ steps.process-comment.outputs.pr_head_sha }}
+          # For issue_comment events, checkout the PR head branch
+          ref: ${{ steps.process-comment.outputs.pr_head_ref }}
           token: ${{ steps.generate-token.outputs.token || secrets.GITHUB_TOKEN }}
 
       - name: Record signature to file