Fix PHPCS link

Author: mattstauffer

CONTRIBUTING.md

@@ -35,6 +35,6 @@ If you need any help with this please don't hesitate to ask.
 
 ## Requirements
 
-- **[PSR-2 Coding Standard](https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-2-coding-style-guide.md)** - The easiest way to apply the conventions is to install [PHP Code Sniffer](https://pear.php.net/package/PHP_CodeSniffer).
+- **[PSR-2 Coding Standard](https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-2-coding-style-guide.md)** - The easiest way to apply the conventions is to install [PHP Code Sniffer](https://github.com/squizlabs/PHP_CodeSniffer).
 - **Tlint styles** - Tighten-specific styles. Tlint is built for apps, so there are some settings that might not make sense in a package, but [download Tlint](https://github.com/tightenco/tlint) and run it on your pull requests to see if it suggests any reasonable changes.
 - **One pull request per feature** - If you want to do more than one thing, send multiple pull requests.