Update composer.json add sf6 compat on collections

Author: sidux

composer.json

@@ -52,7 +52,7 @@
     "fakerphp/faker": "^1.9",
     "firebase/php-jwt": "^6.0.0",
     "guzzlehttp/promises": "^1.4.0",
-    "illuminate/collections": "^8.99",
+    "illuminate/collections": "v8.sf6",
     "monolog/monolog": "^1.25.1 || ^2.8.0 || ^3.0.0",
     "myclabs/deep-copy": "^1.11",
     "nesbot/carbon": "^2.48",