--dependencies - update package kalnoy/nestedset to ^6.0 version

Author: phoenix

composer.json

@@ -10,7 +10,7 @@
     "license": "MIT",
     "require": {
         "php": ">=7.1.0",
-        "kalnoy/nestedset": "^5.0"
+        "kalnoy/nestedset": "^6.0"
     },
     "autoload": {
         "psr-4": {