Update soupsieve from 1.7.2 to 1.9

Author: pyup-bot

requirements.txt

@@ -14,5 +14,5 @@ python-dateutil==2.7.5
 pytz==2018.9
 requests==2.21.0
 six==1.12.0
-soupsieve==1.7.2
+soupsieve==1.9
 urllib3==1.24.1