ultralytics 8.0.21 Windows, segments, YAML fixes (#655)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: corey-nm <109536191+corey-nm@users.noreply.github.com>

ultralytics/yolo/engine/validator.py

@@ -70,7 +70,7 @@ class BaseValidator:
         if self.args.conf is None:
             self.args.conf = 0.001  # default conf=0.001
 
-        self.callbacks = defaultdict(list, {k: v for k, v in callbacks.default_callbacks.items()})  # add callbacks
+        self.callbacks = defaultdict(list, callbacks.default_callbacks)  # add callbacks
 
     @smart_inference_mode()
     def __call__(self, trainer=None, model=None):