Discord.py dep update 3.1 (#2587)

* Dependency update

discord.py==1.0.1
websockets<7

[style]
black==19.3b0

[Docs]
jinja==2.10.1
urllib3==1.24.2

Changes related to breaking changes from discord.py have also been made
to match

As of this commit, help formatter is back to discord.py's default

redbot/cogs/admin/admin.py

@@ -66,7 +66,7 @@ class Admin(commands.Cog):
 
         self.__current_announcer = None
 
-    def __unload(self):
+    def cog_unload(self):
         try:
             self.__current_announcer.cancel()
         except AttributeError: