Pear server is down for a while due to security breach and its not clear that when it will bring back. Since the authoritative origin for PHPCS is squizlabs/PHP_CodeSniffer on Github for a long time, I have replaced the PEAR link for PHPCS with Github in Readme.md.

PEAR server is down
A security breach has been found on the http://pear.php.net webserver, with a tainted go-pear.phar discovered. The PEAR website itself has been disabled until a known clean site can be rebuilt. A more detailed announcement will be on the PEAR Blog once it's back online.

If you have downloaded this go-pear.phar in the past six months, you should get a new copy of the same release version from GitHub (pear/pearweb_phars) and compare file hashes. If different, you may have the infected file.