Move orchestra testbench to dev dependencies

Author: Lloople

composer.json

@@ -18,10 +18,10 @@
     "require": {
         "php": "^7.2",
         "laravel/framework": "^6.0|^7.0",
-        "orchestra/testbench": "^4.0|^5.0",
         "spatie/image-optimizer": "^1.2.0"
     },
     "require-dev": {
+        "orchestra/testbench": "^4.0|^5.0",
         "phpunit/phpunit": "^8.0"
     },
     "autoload": {