test: Do test with the HEAD of docutils

.github/workflows/docutils-latest.yml

@@ -0,0 +1,25 @@
+name: Test with the HEAD of docutils
+
+on:
+  schedule:
+  - cron: "0 0 * * SUN"
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v2
+    - name: Set up Python
+      uses: actions/setup-python@v2
+    - name: Check Python version
+      run: python --version
+    - name: Unpin docutils
+      run: sed -i -e "s/'docutils>=.*'/'docutils'/" setup.py
+    - name: Install graphviz
+      run: sudo apt-get install graphviz
+    - name: Install dependencies
+      run: pip install -U tox codecov
+    - name: Run Tox
+      run: tox -e du-latest -- -vv

tox.ini

@@ -30,6 +30,13 @@ setenv =
 commands=
     python -X dev -m pytest --durations 25 {posargs}
 
+[testenv:du-latest]
+commands =
+    git clone https://repo.or.cz/docutils.git {temp_dir}/docutils
+    python -m pip install {temp_dir}/docutils/docutils
+    rm -rf {temp_dir}/docutils
+    {[testenv]commands}
+
 [testenv:flake8]
 basepython = python3
 description =