docs(typo): fix GitHub capitalization (#72)

README.md

@@ -71,7 +71,7 @@ docker run --rm -e SCAN_URL="https://www.google.com/" lirantal/is-website-vulner
 
 :warning: A modern version of Chrome is assumed to be available when using `is-website-vulnerable`. It may not be safe to assume that this is satisfied automatically on some CI services. For example, [additional configuration](https://docs.travis-ci.com/user/chrome#selecting-a-chrome-version) is necessary for [Travis CI](https://travis-ci.com/).
 
-# Github Action
+# GitHub Action
 Create .github/workflows/is-website-vulnerable.yml with the url that you want scanned:
 
 ```yaml