Update sphinx-rtd-theme from 1.0.0 to 3.0.0

Author: pyup-bot

requirements_dev.txt

@@ -15,7 +15,7 @@ pytz==2021.3
 requests==2.26.0
 snowballstemmer==2.1.0
 Sphinx==4.2.0
-sphinx-rtd-theme==1.0.0
+sphinx-rtd-theme==3.0.0
 sphinxcontrib-applehelp==1.0.2
 sphinxcontrib-devhelp==1.0.2
 sphinxcontrib-htmlhelp==2.0.0