add onnxslim reference (#2314)

README_zh.md

@@ -312,6 +312,12 @@ model = AutoModel(model="paraformer")
 res = model.export(quantize=False)
 ```
 
+### 优化onnx
+```shell
+# pip3 install -U onnxslim
+onnxslim model.onnx model.onnx
+```
+
 ### 测试ONNX
 ```python
 # pip3 install -U funasr-onnx

runtime/python/utils/test_rtf.py

@@ -1,7 +1,7 @@
 import time
 import sys
 import librosa
-from funasr.utils.types import str2bool
+from funasr.utils.type_utils import str2bool
 
 import argparse