[php] fix @implements annotations in PHP client

[IonBazan]

This PR fixes invalid @implements annotations for PHP classes. This is because Model classes should not be generic while current implementation requires users to provide types, which are not known to them (see https://github.com/onfido/api-php-client/issues/26).

This is only reported when using PHPStan with checkGenericClassInNonGenericObjectType: true - https://phpstan.org/blog/generics-in-php-using-phpdocs

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[IonBazan]

Tagging:

• @jebentier
• @dkarlovi (I think you edited these files recently)
• @mandrean
• @jfastnacht
• @ackintosh
• @ybelenko
• @renepardon
  to help review this PR

[wing328]

PHP CI tests passed via https://app.travis-ci.com/github/OpenAPITools/openapi-generator/builds/251563191

[wing328]

@IonBazan thanks for the PR, which has been merged into the master. Do you know if there's any way (e.g. command) to detect these kind of issues in the annotations?

[IonBazan]

Hi @wing328 thanks for merging! The problem was detected using PHPStan with checkGenericClassInNonGenericObjectType: true, when using an API generated with this tool so I'd say it's best to check that during code review as model classes should not be generic.

[wing328]

@IonBazan thanks for the info. will try to add it to the CI later to cover issue like this moving forward.