TASK: Decrease symfony/filesystem version requirements

composer.json

@@ -31,7 +31,7 @@
     "composer-plugin-api": "^1.1",
     "squizlabs/php_codesniffer": "^2.0",
     "symfony/finder": "^3.0",
-    "symfony/filesystem": "^3.0"
+    "symfony/filesystem": "^2.1 || ^3.0"
   },
   "require-dev": {
     "composer/composer": "^1.4",