Update codesniffer to newer version

Author: wilsonge

composer.json

@@ -13,7 +13,7 @@
     ],
     "require": {
         "php": ">=5.4.0",
-        "squizlabs/php_codesniffer": "^3.1"
+        "squizlabs/php_codesniffer": "^3.4"
     },
     "require-dev": {
         "phpunit/phpunit": "^4.8.7"