Update OAI_CONFIG_LIST_sample (#655)

* Update OAI_CONFIG_LIST_sample

replace to api_base from base_url.  api_base is the correct name, otherwise it will error with invalid URL

* put base_url back, add a comment that "api_base" should be used for v0.1.x

* fix typo

* Update OAI_CONFIG_LIST_sample

grammar fix

Co-authored-by: Chi Wang <wang.chi@microsoft.com>

---------

Co-authored-by: Li Jiang <bnujli@gmail.com>
Co-authored-by: Chi Wang <wang.chi@microsoft.com>

OAI_CONFIG_LIST_sample

@@ -1,4 +1,5 @@
-// Please modify the content, remove this comment and rename this file to OAI_CONFIG_LIST to run the sample code.
+// Please modify the content, remove these two lines of comment and rename this file to OAI_CONFIG_LIST to run the sample code.
+// if using pyautogen v0.1.x with Azure OpenAI, please replace "base_url" with "api_base" (line 11 and line 18 below). Use "pip list" to check version of pyautogen installed.
 [
     {
         "model": "gpt-4",