chore: validate readme for pypi

Author: untitaker

tox.ini

@@ -49,6 +49,7 @@ deps =
     flask: flask-login
     linters: black
     linters: flake8
+    linters: docutils
 setenv =
     PYTHONDONTWRITEBYTECODE=1
     TESTPATH=tests
@@ -75,3 +76,4 @@ commands =
 commands =
     flake8
     black --check .
+    python setup.py check -r -s  # check if the readme will break on PyPI