Add reason to TextChannel.create_webhook

The reason parameter does not work with webhook deletes or edits so
they're not added. Probably a Discord bug.

discord/channel.py

@@ -403,13 +403,16 @@ class TextChannel(discord.abc.Messageable, discord.abc.GuildChannel, Hashable):
         data = await self._state.http.channel_webhooks(self.id)
         return [Webhook.from_state(d, state=self._state) for d in data]
 
-    async def create_webhook(self, *, name, avatar=None):
+    async def create_webhook(self, *, name, avatar=None, reason=None):
         """|coro|
 
         Creates a webhook for this channel.
 
         Requires :attr:`~.Permissions.manage_webhooks` permissions.
 
+        .. versionchanged:: 1.1.0
+            Added the ``reason`` keyword-only parameter.
+
         Parameters
         -------------
         name: :class:`str`
@@ -417,6 +420,8 @@ class TextChannel(discord.abc.Messageable, discord.abc.GuildChannel, Hashable):
         avatar: Optional[:class:`bytes`]
             A :term:`py:bytes-like object` representing the webhook's default avatar.
             This operates similarly to :meth:`~ClientUser.edit`.
+        reason: Optional[:class:`str`]
+            The reason for creating this webhook. Shows up in the audit logs.
 
         Raises
         -------
@@ -434,7 +439,7 @@ class TextChannel(discord.abc.Messageable, discord.abc.GuildChannel, Hashable):
         if avatar is not None:
             avatar = utils._bytes_to_base64_data(avatar)
 
-        data = await self._state.http.create_webhook(self.id, name=str(name), avatar=avatar)
+        data = await self._state.http.create_webhook(self.id, name=str(name), avatar=avatar, reason=reason)
         return Webhook.from_state(data, state=self._state)
 
 class VoiceChannel(discord.abc.Connectable, discord.abc.GuildChannel, Hashable):

discord/http.py

@@ -537,14 +537,15 @@ class HTTPClient:
 
     # Webhook management
 
-    def create_webhook(self, channel_id, *, name, avatar=None):
+    def create_webhook(self, channel_id, *, name, avatar=None, reason=None):
         payload = {
             'name': name
         }
         if avatar is not None:
             payload['avatar'] = avatar
 
-        return self.request(Route('POST', '/channels/{channel_id}/webhooks', channel_id=channel_id), json=payload)
+        r = Route('POST', '/channels/{channel_id}/webhooks', channel_id=channel_id)
+        return self.request(r, json=payload, reason=reason)
 
     def channel_webhooks(self, channel_id):
         return self.request(Route('GET', '/channels/{channel_id}/webhooks', channel_id=channel_id))