Fix certain parameters not being respected in Guild.create_forum

discord/http.py

@@ -1417,6 +1417,8 @@ class HTTPClient:
             'rtc_region',
             'video_quality_mode',
             'default_auto_archive_duration',
+            'default_thread_rate_limit_per_user',
+            'available_tags',
         )
         payload.update({k: v for k, v in options.items() if k in valid_keys and v is not None})