docs: update README

Signed-off-by: Mike Shaw <mike.shaw@dwp.gsi.gov.uk>

Author: Mike Shaw

README.md

@@ -5,7 +5,7 @@ Shareable [`eslint`](http://eslint.org) config enforcing our lint and style conv
 ## Getting started
 
 ```sh
-npm install --save-dev @dwp/eslint-config-base eslint
+npm install --save-dev @dwp/eslint-config-mocha eslint
 ```
 
 ## Rules