Laravel 6 bump (#22)

* Laravel 6 bump

* Delete .phpunit.result.cache

* More conventional version numbers

Author: SiebeVE

composer.json

@@ -15,14 +15,14 @@
   "require": {
     "php": ">=7.1",
     "vlucas/phpdotenv": "3.*",
-    "illuminate/console": "5.*",
-    "illuminate/support": "5.*"
+    "illuminate/console": "5.*|^6.0",
+    "illuminate/support": "5.*|^6.0"
   },
   "require-dev": {
-    "phpunit/phpunit": "^7.5",
+    "phpunit/phpunit": "^7.5|^8.3",
     "mikey179/vfsstream": "^1.6",
     "mockery/mockery": "^1.0",
-    "orchestra/testbench": "~3.8"
+    "orchestra/testbench": "~3.8|^4.0"
   },
   "license": "MIT",
   "authors": [