I have only upgraded to Laravel ^6.0 from 5.8*.
On running $ composer require laravel/passport
I have got error message "Package zendframework/zend-diactoros is abandoned, you should avoid using it. Use laminas/laminas-diactoros instead."
I have installed laminas-json
Will that suffice?
https://www.zend.com/blog/what-status-zend-framework-transition-laminas
everything zend framework is being transitioned to laminas open source project. There's a lot of projects going to be popping up these messages as zend.