Removes references to ACCESS_KEY in README.md. Replaces with YOUR_ACCESS_KEY.

Author: max-inanc

README.md

@@ -35,7 +35,7 @@ import messagebird
 Then, create an instance of **messagebird.Client**:
 
 ```python
-client = messagebird.Client('test_gshuPaZoeEG6ovbc8M79w0QyM')
+client = messagebird.Client('YOUR_ACCESS_KEY')
 ```
 
 Now you can query the API for information or send a request. For example, if we want to request our balance information you'd do something like this:
@@ -83,7 +83,7 @@ Conversations WhatsApp Sandbox
 To use the whatsapp sandbox you need to add `messagebird.Feature.ENABLE_CONVERSATIONS_API_WHATSAPP_SANDBOX` to the list of features you want enabled. Don't forget to replace `YOUR_ACCESS_KEY` with your actual access key.
 
 ```python
-  client = messagebird.Client('1ekjMs368KTRlP0z6zfG9P70z', features=[messagebird.Feature.ENABLE_CONVERSATIONS_API_WHATSAPP_SANDBOX])
+client = messagebird.Client('YOUR_ACCESS_KEY', features=[messagebird.Feature.ENABLE_CONVERSATIONS_API_WHATSAPP_SANDBOX])
 ```
 
 Documentation