Add support for Cake 5.x (#7)

* Update dependencies

* Update CI versioning

* Upgrade fixture system

* Remove RequestHandler in test app

* Update types

* Create version map

* Add new PHPunit cache folder to ignore

* Formatting

* Add CakePHP's global functions to composer load

* Migrate PHPunit configuration

* Change minimum stability back to stable

* Change strategy in loading CakePHP's global functions

* Fix global functions require path

* Move require global to tests bootstrap

Merge pull request #4 from mentisy/allow-plugin

Allow codesniffer plugin for composer

Merge pull request #2 from mentisy/fix-composer-versioning

Fix versioning to allow up-to breaking changes

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