Update README

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

README.md

@@ -23,8 +23,8 @@ to generate text embeddings for given code "" and text description "".
 import towhee
 
 (
-    towhee.dc([""])
-          .text_embedding.transformers(model_name="distilbert-base-cased")
+    towhee.dc(['find max value', 'def max(a,b): if a>b: return a else return b'])
+          .code_search.codebert(model_name='huggingface/CodeBERTa-small-v1')
 )
 ```
 
@@ -34,8 +34,8 @@ import towhee
 import towhee
 
 (
-    towhee.dc['text'](["Hello, world."])
-          .text_embedding.transformers['text', 'vec'](model_name="distilbert-base-cased")
+    towhee.dc['text'](['find max value', 'def max(a,b): if a>b: return a else return b'])
+          .code_search.codebert['text', 'embedding'](model_name='huggingface/CodeBERTa-small-v1')
           .show()
 )
 ```