Update dependencies

Author: AlexanderPoellmann

composer.json

@@ -21,11 +21,11 @@
     ],
     "require": {
         "php"                   : ">=5.6.4|^7.0",
-        "illuminate/support"    : ">=5.1",
-        "illuminate/database"   : ">=5.1"
+        "illuminate/support"    : ">=5.3",
+        "illuminate/database"   : ">=5.3"
     },
     "require-dev": {
-        "laravel/framework" : "5.4.*",
+        "laravel/framework" : "5.3.*",
         "mockery/mockery" : "0.9.*",
         "phpunit/phpunit" : "^6.0",
         "doctrine/dbal"   : "2.5.x"