BUGFIX: Fix version constraints to correct flow versions

Author: Bastian Heist

composer.json

@@ -22,8 +22,8 @@
         "source": "https://github.com/sandstorm/UserManagement"
     },
     "require": {
-        "neos/flow": "dev-master",
-        "neos/swiftmailer": "dev-master"
+        "neos/flow": "^4.0",
+        "neos/swiftmailer": "^6.0"
     },
     "autoload": {
         "psr-4": {