Add support for guild descriptions

discord/guild.py

@@ -758,6 +758,9 @@ class Guild(Hashable):
         ----------
         name: str
             The new name of the guild.
+        description: str
+            The new description of the guild. This is only available to guilds that
+            contain `VERIFIED` in :attr:`Guild.features`.
         icon: bytes
             A :term:`py:bytes-like object` representing the icon. Only PNG/JPEG supported.
             Could be ``None`` to denote removal of the icon.

discord/http.py

@@ -568,7 +568,7 @@ class HTTPClient:
         valid_keys = ('name', 'region', 'icon', 'afk_timeout', 'owner_id',
                       'afk_channel_id', 'splash', 'verification_level',
                       'system_channel_id', 'default_message_notifications',
-                      'explicit_content_filter')
+                      'description', 'explicit_content_filter')
 
         payload = {
             k: v for k, v in fields.items() if k in valid_keys