feat: FrankenPHP extensions

[dunglas]

See: #1649 and https://github.com/dunglas/frankenphp-etcd

[withinboredom]

this is gonna take awhile...

[alexandre-daubois]

Here is the docs PR: https://github.com/php/frankenphp/pull/1652

[dunglas]

The CI failure looks related to a change in SPC. Do you know what we're doing wrong @henderkes @crazywhalecc? It looks like we pass the --build-embed flag as usual.

[crazywhalecc]

Seems that making --build-embed as optional causes this error. Workaround: move --build-embed at the end of command. I didn't expect that passing the parameter as InputOption::OPTIONAL would cause the extensions to be recognized as a value, maybe I need to revert the previous PR or find another way to avoid it being read as a value.

[henderkes]

should be fixed now, we reverted to a boolean flag

for some reason, the framework we used for option parsing defaults --build-embed to null, rather than true, like it does without a value to pass.

[alexandre-daubois]

🎉