Fix GI import warning

sublime_music/adapters/adapter_base.py

@@ -2,6 +2,7 @@ import abc
 import copy
 import hashlib
 import uuid
+import gi
 from dataclasses import dataclass
 from datetime import timedelta
 from enum import Enum
@@ -18,6 +19,7 @@ from typing import (
     Tuple,
 )
 
+gi.require_version('Gtk', '3.0')
 from gi.repository import Gtk
 
 try: