Update README.md

Author: sn0wcat

README.md

@@ -16,7 +16,7 @@ Use the extension to copy the cookies to the clipboard, paste them to the comman
 
 ## MindSphere Development Proxy
 
-You can also use the exentsion to simplify the start of [MindSphere Development Proxy](https://opensource.mindsphere.io/docs/mindconnect-nodejs/cli/development-proxy.html) in a similar fashion. Just copy/paste the cookies to the command line and [start the development proxy](https://opensource.mindsphere.io/docs/mindconnect-nodejs/cli/development-proxy.html#tab1anchor1).
+You can also use the extension to simplify the start of [MindSphere Development Proxy](https://opensource.mindsphere.io/docs/mindconnect-nodejs/cli/development-proxy.html) in a similar fashion. Just copy/paste the cookies to the command line and [start the development proxy](https://opensource.mindsphere.io/docs/mindconnect-nodejs/cli/development-proxy.html#tab1anchor1).
 
 ![cli](images/proxy-cookie.png)