Bump deps

[lnicola]

The major changes here are actix-web and postgres, with the latter being especially painful.

A couple of noteworthy things here:

• we no longer use cached prepared statements; they're gone from postgres because you're supposed to cache them externally, but they're probably bound to a connection but we use a connection per request, so I doubt they worked even before
• postgres now uses a tokio runtime for each blocking, leading to panics (you can't start a run-time from another); I added some actix_web::web::block calls to dispatch those on a thread pool, but that's a good idea anyway since it leaves the reactor threads free for network transfer. Ideally, we'd use the async Postgres client instead, but the datasets are not async yet.
• r2d2_postgres is annoying

[lnicola]

PS: I'm not sure about TLS support -- I haven't tested it, and I don't know whether the system certificate store is imported automatically or not. But that didn't seem to happen before, in any case.

[pka]

Thanks a lot for this PR, @lnicola !
The actix-web update was on my todo list. Seems you have been more successful with upgrading Postgres than me (https://github.com/t-rex-tileserver/t-rex/tree/pg17)! Would be nice to chat about async PG things. Maybe you look into the GeoRust discord once?

[lnicola]

I'll try to join the Discord, but not that I've never used any Rust Postgres client until this PR, so no promises in that direction.