Increase minimum PHPCS version

Author: joelambert

composer.json

@@ -9,7 +9,7 @@
         "mockery/mockery": "^1.0.0",
         "brain/monkey": "^2.0.2",
         "satooshi/php-coveralls": "^1.0",
-        "squizlabs/php_codesniffer": "^3.2",
+        "squizlabs/php_codesniffer": "^3.5",
         "codedungeon/phpunit-result-printer": "^0.4.4"
     },
     "autoload": {