Update sphinx from 2.2.0 to 2.2.1

Author: pyup-bot

dev-requirements.txt

@@ -20,7 +20,7 @@ pyroma==2.5  # Packaging best practices checker
 pytest-cov==2.8.1  # Measure code coverage
 pytest==5.2.1  # Test runners
 PyYAML==5.1.2
-Sphinx==2.2.0
+Sphinx==2.2.1
 sphinx-autodoc-typehints==1.9.0
 sphinxcontrib-spelling==4.3.0
 twine==2.0.0