CakePHP 5 compatibility

[BGehrels]

Since CakePHP 5 was released recently, this branch tries to get CakePdf running with it.

It's a first rough draft (tested with CakePHP 5.0.0 and PHP 8.1.2 and 8.2.8 and Mpdf v8.2.0).

I can not say if this really still works with cakephp 2 / phpunit 8 / phpunit 9 (i guess not, but did not find the time to test it yet). I also do not know if such backwards compatibility is desired by the maintainers of this package or unnecessary effort.

But: i would love to get the Cake 5 adoption process started, so here is the first draft.

Another open topic: As the RequestHandlerComponent was removed, the guidance (and probably also the code) regarding content negotiation needs to be updated

[BGehrels]

Just tested against CakePHP 4: the field type declarations in the PdfView must be present with CakePHP 5 and must not be present with CakePHP 4, so it seems like there is no easy way to support both.

As CakePHP5 only works with PHPUnit 10, this also means no support for PHPUnit 8/9 anymore.

[BGehrels]

Build chain is adapted to the compatibility requirements of CakePHP 5 and now green.

One could use this release to properly type the all public facing methods. If you update psalm and phpcs to their latest versions, they will give you a plethora of warnings & errors about that. But: if you want to do this properly, i think it involves splitting the Get/Set methods in CakePdf in proper getters and setters. That is a lot of work and exceeds my capacities at the moment.

[ADmad]

Please target your changes to the already existing cake5 branch.

[ADmad]

I can not say if this really still works with cakephp 2 / phpunit 8 / phpunit 9 (i guess not, but did not find the time to test it yet). I also do not know if such backwards compatibility is desired by the maintainers of this package or unnecessary effort.

The CakePHP 5 compatible version will be a new major version bump for the plugin, so no need to worry about backwards compatibility.