Update idna from 2.8 to 2.9

Author: pyup-bot

requirements.txt

@@ -12,7 +12,7 @@ attrs==19.3.0             # via aiohttp
 cffi==1.14.0              # via pycares
 chardet==3.0.4            # via aiohttp
 fonttools==4.4.0
-idna==2.8                 # via yarl
+idna==2.9                 # via yarl
 multidict==4.7.4          # via aiohttp, yarl
 pycares==3.1.1            # via aiodns
 pycparser==2.19           # via cffi