remove tf support in event_tokenizer

Author: iLampard

easy_tpp/preprocess/event_tokenizer.py

@@ -4,7 +4,7 @@
 
 import numpy as np
 
-from easy_tpp.utils import is_torch_available, logger, TruncationStrategy, PaddingStrategy, \
+from easy_tpp.utils import logger, TruncationStrategy, PaddingStrategy, \
     TensorType, is_torch_device, requires_backends, is_numpy_array, py_assert