Trigger PR testing when PR opened by GitHub Actions is marked as ready for review

PRs created by GitHub Actions don't kick off further actions (https://github.com/peter-evans/create-pull-request/blob/d57e551ebc1a16dee0b8c9ea6d24dba7627a6e35/docs/concepts-guidelines.md#triggering-further-workflow-runs).
As a workaround, we mark automerge PRs that are created by GitHub actions as draft and trigger the GitHub actions by marking the PR as ready for review. But we don't want to re-trigger testing this when a normal user's PR is marked as ready for review.

Author: ahoppen

.github/workflows/pull_request.yml

@@ -2,7 +2,7 @@ name: Pull request
 
 on:
   pull_request:
-    types: [opened, reopened, synchronize]
+    types: [opened, reopened, synchronize, ready_for_review]
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
@@ -12,11 +12,17 @@ jobs:
   tests:
     name: Test
     uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
+    # PRs created by GitHub Actions don't kick off further actions (https://github.com/peter-evans/create-pull-request/blob/d57e551ebc1a16dee0b8c9ea6d24dba7627a6e35/docs/concepts-guidelines.md#triggering-further-workflow-runs).
+    # As a workaround, we mark automerge PRs that are created by GitHub actions as draft and trigger the GitHub actions by marking the PR as ready for review. But we don't want to re-trigger testing this when a normal user's PR is marked as ready for review.
+    if: (github.event.action != 'ready_for_review') || (github.event.action == 'ready_for_review' && github.event.pull_request.user.login == 'github-actions[bot]')
     with:
       linux_exclude_swift_versions: "[{\"swift_version\": \"5.8\"}]"
   soundness:
     name: Soundness
     uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main
+    # PRs created by GitHub Actions don't kick off further actions (https://github.com/peter-evans/create-pull-request/blob/d57e551ebc1a16dee0b8c9ea6d24dba7627a6e35/docs/concepts-guidelines.md#triggering-further-workflow-runs).
+    # As a workaround, we mark automerge PRs that are created by GitHub actions as draft and trigger the GitHub actions by marking the PR as ready for review. But we don't want to re-trigger testing this when a normal user's PR is marked as ready for review.
+    if: (github.event.action != 'ready_for_review') || (github.event.action == 'ready_for_review' && github.event.pull_request.user.login == 'github-actions[bot]')
     with:
       license_header_check_project_name: "Swift.org"
       api_breakage_check_allowlist_path: "api-breakages.txt"