CI: Comment when done [wheel build]

.github/workflows/build_wheels.yml

@@ -4,14 +4,14 @@
 # https://github.com/airspeed-velocity/asv/blob/main/.github/workflows/wheels.yml
 # include [wheel build] in the commit to trigger wheel builds
 name: Build wheels
-on: [push, pull_request, workflow_dispatch]
+on: [push, workflow_dispatch, pull_request_target]
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
 permissions:
-  contents: read # to fetch code (actions/checkout)
+  contents: write # for the comment action
 
 jobs:
   get_commit_message:
@@ -109,3 +109,20 @@ jobs:
           name: artifact
           path: dist
       - uses: pypa/gh-action-pypi-publish@release/v1
+
+  comment_on_pr:
+    if: >-
+      contains(needs.get_commit_message.outputs.message, '[wheel build]') ||
+      github.event_name == pull_request_target'
+    needs: [build_wheels, build_sdist]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Comment PR
+        uses: thollander/actions-comment-pull-request@v1
+        with:
+          message: |
+                        Artifacts generated for this PR:
+                        - [Wheels](${{ github.server_url }}/${{ github.repository }}/actions/artifacts/)
+                        Please download and test these to validate the PR.
+          comment_includes: "Artifacts generated for this PR"
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}