Update README.md

Author: princebaretto99

README.md

@@ -1,6 +1,8 @@
 # CodeceptJS-Browserstack
 
 # Integrating CodeceptJS <a href="https://codecept.io/"><img src="https://codecept.io/logo.svg" alt="Node.js" height="22" /></a> with BrowserStack <a href="https://browserstack.com"><img src="https://www.browserstack.com/blog/favicon.png" alt="BrowserStack" height="22" /></a>
+## Prerequisite
+* [Node.js](https://nodejs.org/en/download/) version >= 12.0
 
 ## Setup
 * Clone the repo
@@ -20,7 +22,7 @@
 
   ```
   export BROWSERSTACK_USERNAME=<browserstack-username> &&
-  export BROWSERSTACK_ACCESSKEY=<browserstack-access-key>
+  export BROWSERSTACK_ACCESS_KEY=<browserstack-access-key>
   ```
 
 ## Addtional Resources