README: update URL for downloading the PHAR

The GH Pages website has been re-activated under a new domain - phars.phpcodesniffer.com -.

The PHARs can now be downloaded from that domain and PHIVE should work as well, though a PR to phar.io will be needed to update the PHIVE alias redirect.

Author: jrfnl

README.md

@@ -17,12 +17,12 @@ If you're using PHP_CodeSniffer as part of a team, or you're running it on a [CI
 The easiest way to get started with PHP_CodeSniffer is to download the Phar files for each of the commands:
 ```
 # Download using curl
-curl -OL https://squizlabs.github.io/PHP_CodeSniffer/phpcs.phar
-curl -OL https://squizlabs.github.io/PHP_CodeSniffer/phpcbf.phar
+curl -OL https://phars.phpcodesniffer.com/phpcs.phar
+curl -OL https://phars.phpcodesniffer.com/phpcbf.phar
 
 # Or download using wget
-wget https://squizlabs.github.io/PHP_CodeSniffer/phpcs.phar
-wget https://squizlabs.github.io/PHP_CodeSniffer/phpcbf.phar
+wget https://phars.phpcodesniffer.com/phpcs.phar
+wget https://phars.phpcodesniffer.com/phpcbf.phar
 
 # Then test the downloaded PHARs
 php phpcs.phar -h