Fix blocking .well-known path for FrankenPHP

[marns93]

Fixes: https://github.com/serversideup/docker-php/issues/626

The newest variation frankenphp is blocking everything under .well-known/. The following line is responsible for this https://github.com/serversideup/docker-php/blob/9b6868e8facc60b4f17a8898c8eb85c3db10c801/src/variations/frankenphp/etc/frankenphp/Caddyfile#L131

In this PR I've whitelisted some commonly used paths under .well-known/. For security reasons I don't want to allow everything, so I've whitelisted some of them. The list can be extended in the future.

[jaydrogers]

Thanks for the PR! I will review soon 👍