fix: move UTC assignment after imports to fix ruff E402

Author: yunjinqi

backtrader/resamplerfilter.py

@@ -19,13 +19,13 @@
 """
 from datetime import datetime, timedelta, timezone
 
-# Python 3.11+ has datetime.UTC, earlier versions use timezone.utc
-UTC = timezone.utc
-
 from .dataseries import TimeFrame, _Bar
 from .parameters import ParameterizedBase
 from .utils.date import date2num, num2date
 
+# Python 3.11+ has datetime.UTC, earlier versions use timezone.utc
+UTC = timezone.utc
+
 
 # This class is only used in the _checkbarover function
 # chkdata = DTFaker(data, forcedata) if fromcheck else data