Bump discord.py to 1.7.0 (#4928)

* Bump discord.py, but to the git version for now

* Import GuildConverter from d.py and deprecate our implementation

* Import PartialMessageConverter in our commands extension

* Use newly added `Cog.has_error_handler()` rather than private method

* Update snowflake regex to use 20 as max length

See Rapptz/discord.py#6501

* Use new supported way for custom cooldown buckets

* Include group args in command signature

* Update code to use `Client.close()` over `Client.logout()`

* Add StageChannelConverter and StoreChannelConverter

* Fix AttributeError in licenseinfo

redbot/core/bot.py

@@ -1664,9 +1664,9 @@ class RedBase(
         await asyncio.sleep(delay)
         await _delete_helper(message)
 
-    async def logout(self):
+    async def close(self):
         """Logs out of Discord and closes all connections."""
-        await super().logout()
+        await super().close()
         await drivers.get_driver_class().teardown()
         try:
             if self.rpc_enabled:
@@ -1691,7 +1691,7 @@ class RedBase(
         else:
             self._shutdown_mode = ExitCodes.RESTART
 
-        await self.logout()
+        await self.close()
         sys.exit(self._shutdown_mode)
 
     async def _core_data_deletion(