OpenBSD CI appears to be broken

[fogti]

https://cirrus-ci.com/task/6170537933668352

pkg_add git rust
https://cdn.openbsd.org/pub/OpenBSD/7.5/packages/amd64/: no such dir
Can't find git
Can't find rust

[taiki-e]

See smol-rs/async-io#222 (comment).

[taiki-e]

This issue has been fixed in upstream.