readme fixes

Author: rchougule

README.md

@@ -20,7 +20,7 @@ If you want to test your open source project on BrowserStack, then [sign-up here
 
 * [setup-local](./setup-local): This Action downloads and starts the appropriate BrowserStackLocal binary, thereby creating a secure tunnel connection from the GitHub Actions runner environment to the BrowserStack device cloud. This secure tunnel will be used by the remote browsers in BrowserStack to access your web application hosted in the GitHub Actions runner environment. **You do not need this Action if the application to be tested is accessible over the public internet.**
 
-## Pre-requisites
+## Prerequisites
 * You should set your BrowserStack Username and Access Key as GitHub Secrets, i.e. `BROWSERSTACK_USERNAME` and `BROWSERSTACK_ACCESS_KEY` respectively.
 
 ## Usage