Update README

Signed-off-by: Jael Gu <mengjia.gu@zilliz.com>

README.md

@@ -53,20 +53,20 @@ Create the operator via the following factory method
 
 **Parameters:**
 
-&nbsp   ***model_name***: *str*
+***model_name***: *str*
 
-&nbsp   The model name in string. The default value is "resnet34".
+The model name in string. The default value is "resnet34".
 Refer [Timm Docs](https://fastai.github.io/timmdocs/#List-Models-with-Pretrained-Weights) to get a full list of supported models.
 
 
-&nbsp   ***num_classes***: *int*
+***num_classes***: *int*
 
-&nbsp   The number of classes. The default value is 1000.
+The number of classes. The default value is 1000.
 It is related to model and dataset.
 
-&nbsp   ***skip_preprocess***: *bool*
+***skip_preprocess***: *bool*
 
-&nbsp   The flag to control whether to skip image preprocess.
+The flag to control whether to skip image preprocess.
 The default value is False.
 If set to True, it will skip image preprocessing steps (transforms).
 In this case, input image data must be prepared in advance in order to properly fit the model.
@@ -81,17 +81,17 @@ It uses the pre-trained model specified by model name to generate an image embed
 
 **Parameters:**
 
-&nbsp   ***img***: *towhee.types.Image (a sub-class of numpy.ndarray)*
+***img***: *towhee.types.Image (a sub-class of numpy.ndarray)*
 
-&nbsp 	The decoded image data in numpy.ndarray.
+The decoded image data in numpy.ndarray.
 
 
 
 **Returns**:
 
-&nbsp   *numpy.ndarray*
+*numpy.ndarray*
 
-&nbsp   The image embedding extracted by model.
+The image embedding extracted by model.