remove eslint-plugin-standard

Fixes: standard/standard#1316

README.md

@@ -34,7 +34,7 @@ provided in `eslint-config-standard`.
 Here's how to install everything you need:
 
 ```bash
-npm install --save-dev babel-eslint eslint-config-standard eslint-config-standard-react eslint-plugin-standard eslint-plugin-promise eslint-plugin-import eslint-plugin-node eslint-plugin-react
+npm install --save-dev babel-eslint eslint-config-standard eslint-config-standard-react eslint-plugin-promise eslint-plugin-import eslint-plugin-node eslint-plugin-react
 ```
 
 Then, add this to your `.eslintrc` file: