Unified model loading with backwards compatibility (#132)

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

ultralytics/yolo/v8/segment/train.py

@@ -17,7 +17,7 @@ from ultralytics.yolo.utils.torch_utils import de_parallel
 class SegmentationTrainer(v8.detect.DetectionTrainer):
 
     def load_model(self, model_cfg=None, weights=None, verbose=True):
-        model = SegmentationModel(model_cfg or weights["model"].yaml, ch=3, nc=self.data["nc"], verbose=verbose)
+        model = SegmentationModel(model_cfg or weights.yaml, ch=3, nc=self.data["nc"], verbose=verbose)
         if weights:
             model.load(weights, verbose)
         return model