Add Gitea Actions workflow (from GitHub)

.gitea/workflows/pull_request.yml

@@ -0,0 +1,26 @@
+name: Pull Request Docs Check
+
+on: [pull_request]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: https://github.com/actions/checkout@v2
+    - name: Prepare
+      run: |
+        sudo apt-get update -y
+        sudo apt-get install -y git python3-pip mandoc
+        pip install -r docs/requirements.txt
+    - name: Gen_man_pages
+      run: make man
+    - name: Gen_feature_matrix
+      run: make feature_matrix
+    - name: Gen_sphinx
+      uses: ammaraskar/sphinx-action@master
+      with:
+        docs-folder: "docs/"
+    - uses: https://github.com/actions/upload-artifact@v2
+      with:
+        name: DocumentationHTML
+        path: docs/_build/html/