PYTHON-4663 Fix json_util datetimems check

Author: ShaneHarvey

bson/json_util.py

@@ -125,7 +125,7 @@
 from bson.code import Code
 from bson.codec_options import CodecOptions, DatetimeConversion
 from bson.datetime_ms import (
-    _MIN_UTC_MS,
+    _MAX_UTC_MS,
     EPOCH_AWARE,
     DatetimeMS,
     _datetime_to_millis,
@@ -844,7 +844,7 @@ def _encode_binary(data: bytes, subtype: int, json_options: JSONOptions) -> Any:
 def _encode_datetimems(obj: Any, json_options: JSONOptions) -> dict:
     if (
         json_options.datetime_representation == DatetimeRepresentation.ISO8601
-        and 0 <= int(obj) <= _MIN_UTC_MS
+        and 0 <= int(obj) <= _MAX_UTC_MS
     ):
         return _encode_datetime(obj.as_datetime(), json_options)
     elif json_options.datetime_representation == DatetimeRepresentation.LEGACY: