Composer: avoid writing a lock file

Author: fredden

composer.json

@@ -30,5 +30,8 @@
     "dealerdirect/phpcodesniffer-composer-installer": "^1.0 || This Composer plugin will sort out the PHP_CodeSniffer 'installed_paths' automatically.",
     "roave/security-advisories": "dev-master || Helps prevent installing dependencies with known security issues."
   },
-  "prefer-stable" : true
+  "prefer-stable": true,
+  "config": {
+    "lock": false
+  }
 }