[Fix] Fix mmengine dump of tversky ut in dev-1.x (#2001)

Author: MengzhangLI

tests/test_models/test_losses/test_tversky_loss.py

@@ -36,11 +36,12 @@ def test_tversky_lose():
     import os
     import tempfile
 
-    import mmcv
+    import mmengine
     import numpy as np
     tmp_file = tempfile.NamedTemporaryFile()
 
-    mmcv.dump([1.0, 2.0, 3.0], f'{tmp_file.name}.pkl', 'pkl')  # from pkl file
+    mmengine.dump([1.0, 2.0, 3.0], f'{tmp_file.name}.pkl',
+                  'pkl')  # from pkl file
     loss_cfg = dict(
         type='TverskyLoss',
         class_weight=f'{tmp_file.name}.pkl',