Lock autodoc typehints

Author: adamboche

dev-requirements.txt

@@ -45,8 +45,9 @@ pyyaml==5.1.1             # via watchdog
 requests==2.22.0          # via sphinx
 six==1.12.0               # via astroid, cuvner, packaging, pytest, tox
 snowballstemmer==1.2.1    # via sphinx
+sphinx-autodoc-typehints==1.6.0
 sphinx-rtd-theme==0.4.3
-sphinx==2.1.0             # via sphinx-rtd-theme
+sphinx==2.1.0             # via sphinx-autodoc-typehints, sphinx-rtd-theme
 sphinxcontrib-applehelp==1.0.1  # via sphinx
 sphinxcontrib-devhelp==1.0.1  # via sphinx
 sphinxcontrib-htmlhelp==1.0.2  # via sphinx