feat(ci): request reviews from API experts (nodejs#8040)

Author: avivkeller

.github/CODEOWNERS

@@ -41,6 +41,10 @@ SECURITY.md @nodejs/security-wg
 apps/site/pages/en/blog/release @nodejs/releasers
 apps/site/pages/en/blog/announcements @nodejs/releasers
 
-# Specific content
+# The following users DO NOT have write access, and their review is requested
+# via a GitHub action.
+apps/site/pages/en/learn/diagnostics @nodejs/diagnostics
 apps/site/pages/en/learn/getting-started/security-best-practices.md @nodejs/security-wg
+apps/site/pages/en/learn/manipulating-files @nodejs/fs
+apps/site/pages/en/learn/test-runner @nodejs/test_runner
 apps/site/pages/en/learn/typescript @nodejs/typescript

.github/workflows/request-codeowner-review.yml

@@ -0,0 +1,22 @@
+name: Request Codeowner Reviews
+
+on:
+  pull_request_target:
+    types: [opened]
+
+permissions:
+  contents: read
+  pull-requests: write
+
+jobs:
+  request-reviews:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+
+      - name: Request Codeowner Reviews
+        uses: pkgjs/request-codeowner-review@d39b61c5e1399655dce6287b3b119af93dee235a # v1.1.0
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          output-mode: comment