Add roave/security-advisories package

Flags any packages with known security issues.

Author: GaryJones

composer.json

@@ -3,14 +3,15 @@
     "description": "A PHPCS sniff to detect problems with variables.",
     "type": "phpcodesniffer-standard",
     "license": "BSD",
-    "require" : {
-        "php" : ">=5.4.0",
-        "squizlabs/php_codesniffer" : "^3.0.2"
-    },
     "authors": [
         {
             "name": "Payton Swick",
             "email": "payton@foolord.com"
         }
-    ]
+    ],
+    "require" : {
+        "php" : ">=5.4.0",
+        "squizlabs/php_codesniffer" : "^3.0.2",
+        "roave/security-advisories": "dev-master"
+    }
 }