Composer update

* updated Laravel to v5.6.38
* Added laravel tinker in dev dependencies

vendor/laravel/tinker/config/tinker.php

@@ -0,0 +1,18 @@
+<?php
+
+return [
+
+    /*
+    |--------------------------------------------------------------------------
+    | Alias Blacklist
+    |--------------------------------------------------------------------------
+    |
+    | Typically, Tinker automatically aliases classes as you require them in
+    | Tinker. However, you may wish to never alias certain classes, which
+    | you may accomplish by listing the classes in the following array.
+    |
+    */
+
+    'dont_alias' => [],
+
+];