Readme - composer require fix

                    
|Q             |A  |
|---           |---|
|Bug Fix?:     |y  |
|New Feature?: |n  |
|BC Breaks?:   |n  |
|Deprecations?:|n  |
|Tests Pass?:  |y  |
|Fixed Tickets:|   |
|License:      |MIT|
|Doc PR:       |   |
                    

Your requirements could not be resolved to an installable set of packages.