Add php8.1-intl as a dependency

[LtdJorge]

The initial setup with composer fails otherwise

[QuintenQVD0]

it seems like you are the only one having this issue, as nobody else reported it.

I think this can be closed

[Boy132]

it seems like you are the only one having this issue, as nobody else reported it.

I think this can be closed

Some users on the discord had this problem too.
But I can't remember the exact circumstances/ system setup where this problem occured.