Remove support for PHP 8.0

[fezfez]

since mezzio has dropped support for php 8, there is no need that mezzio-swoole support it.

see https://github.com/mezzio/mezzio/commit/db61148892417775571656550c7a8a67a2a7c519

[gsteel]

Thanks @fezfez - Can you also remove the 'ignore-platform-reqs' in .laminas-ci.json please? https://github.com/mezzio/mezzio-swoole/blob/161be43bb9b186a0199e172db506a8c811c15692/.laminas-ci.json#L6-L8

[fezfez]

Thanks @fezfez - Can you also remove the 'ignore-platform-reqs' in .laminas-ci.json please?

https://github.com/mezzio/mezzio-swoole/blob/161be43bb9b186a0199e172db506a8c811c15692/.laminas-ci.json#L6-L8

done