Diactoros Detection Fails after laminas release 2.6

[gsteel]

Because laminas/diactoros now conflicts with zend/diactoros, and the zend framework bridge component is getting deprecated and removed from most Laminas repos, discovery fails if you're using recent laminas versions.

This could be solved either by adding the Laminas equivalents to common classes, or by adding the zend framework bridge component to composer.json.

Assuming the former would be preferable, I'll try and get a pull together shortly.