squashto: Require slevomat/coding-standard

Author: mmoll

composer.json

@@ -26,7 +26,7 @@
     },
     "require": {
         "squizlabs/php_codesniffer": "^3.3.1",
-        "slevomat/coding-standard": "^6.4"
+        "slevomat/coding-standard": "^7.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^5.0 || ^6.0 || ^7.0"