Laravel deprecated that array_except function in favour of a different naming convention:
https://laracasts.com/discuss/channels/laravel/array-except-is-deprecated-in-laravel-58
So this means that you are using some incompatible dependencies.
My two cents here: The latest illuminate/support package doesn’t offer the array_except anymore, hence other libraries have issues now.
You may also be interested in the Sage 9.x update branch:
https://discourse.roots.io/t/sage-9-1-please-test/20067