Update sphinxcontrib-spelling from 4.2.1 to 4.3.0

Author: pyup-bot

dev-requirements.txt

@@ -21,7 +21,7 @@ pytest==4.6.0  # Test runners
 PyYAML==5.1.1
 Sphinx==2.1.0
 sphinx-autodoc-typehints==1.6.0
-sphinxcontrib-spelling==4.2.1
+sphinxcontrib-spelling==4.3.0
 twine==1.13.0
 versioneer==0.18
 vulture==1.0