Update dependencies

Author: tvdijen

composer.json

@@ -23,7 +23,8 @@
     },
     "require-dev": {
         "simplesamlphp/simplesamlphp": "^1.18@RC",
-        "simplesamlphp/simplesamlphp-test-framework": "~0.1.0"
+        "simplesamlphp/simplesamlphp-test-framework": "~0.1.0",
+        "squizlabs/php_codesniffer": "^3.5"
     },
     "support": {
         "issues": "https://github.com/simplesamlphp/simplesamlphp-module-casserver/issues",