Add doc build test with Ruby 4.0 in PR CI

Author: mokuzon

.github/workflows/pull_request.yml

@@ -36,6 +36,21 @@ jobs:
     - run: python3 generate-code.py
     - run: bundle exec rake ci
 
+  build-doc:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    name: Build docs with Ruby 4.0
+    steps:
+    - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      with:
+        submodules: true
+    - uses: ruby/setup-ruby@19a43a6a2428d455dbd1b85344698725179c9d8c # v1.289.0
+      with:
+        ruby-version: '4.0'
+    - run: bundle install
+    - run: bundle exec yard doc
+
   pinact:
     runs-on: ubuntu-latest
     permissions: