Update twine from 1.10.0 to 3.2.0 (#23)

Author: pyup-bot

requirements_dev.txt

@@ -6,7 +6,7 @@ flake8==3.8.4
 tox==3.20.1
 coverage==5.3
 Sphinx==1.7.1
-twine==1.10.0
+twine==3.2.0
 
 pytest==3.8.1
 pytest-aiohttp==0.3.0