fix: PR Linter to handle pull_request_target events

Author: pahud

.github/workflows/pr-linter.yml

@@ -26,8 +26,8 @@ jobs:
   download-if-workflow-run:
     runs-on: ubuntu-latest
     outputs:
-      pr_number: ${{ steps.pr_output.outputs.pr_number }}
-      pr_sha: ${{ steps.pr_output.outputs.pr_sha }}
+      pr_number: ${{ steps.pr_output.outputs.pr_number || steps.pr_output_target.outputs.pr_number }}
+      pr_sha: ${{ steps.pr_output.outputs.pr_sha || steps.pr_output_target.outputs.pr_sha }}
     # if conditions on all individual steps because subsequent jobs depend on this job
     # and we cannot skip it entirely
     steps:
@@ -41,7 +41,7 @@ jobs:
           path: pr/
           search_artifacts: true
 
-      - name: 'Determine PR info'
+      - name: 'Determine PR info from workflow_run'
         # PR info comes from the artifact if downloaded, or GitHub context if not.
         if: github.event_name == 'workflow_run'
         id: 'pr_output'
@@ -56,6 +56,13 @@ jobs:
           echo "pr_number=$(cat pr/pr_number)" >> "$GITHUB_OUTPUT"
           echo "pr_sha=$(cat pr/pr_sha)" >> "$GITHUB_OUTPUT"
 
+      - name: 'Get PR info from pull_request_target event'
+        if: github.event_name == 'pull_request_target'
+        id: 'pr_output_target'
+        run: |
+          echo "pr_number=${{ github.event.pull_request.number }}" >> "$GITHUB_OUTPUT"
+          echo "pr_sha=${{ github.event.pull_request.head.sha }}" >> "$GITHUB_OUTPUT"
+
   validate-pr:
     # Necessary to have sufficient permissions to write to the PR
     permissions: