Implement yaml.safe_load() (#2876)

* Implement yaml.safe_load()

* yaml.safe_dump()

utils/autoanchor.py

@@ -102,7 +102,7 @@ def kmean_anchors(path='./data/coco128.yaml', n=9, img_size=640, thr=4.0, gen=10
 
     if isinstance(path, str):  # *.yaml file
         with open(path) as f:
-            data_dict = yaml.load(f, Loader=yaml.SafeLoader)  # model dict
+            data_dict = yaml.safe_load(f)  # model dict
         from utils.datasets import LoadImagesAndLabels
         dataset = LoadImagesAndLabels(data_dict['train'], augment=True, rect=True)
     else: