Specify an MSRV policy

[tertsdiepraam]

Hi! We depend on this library in domain transitively via moka and just got bit by new requirement that rust 1.76 or later should be used. This is fine of course, but I wanted to ask if you could specify some MSRV policy or provide the rust-version key in Cargo.toml, which will help prevent issues like this once the MSRV-dependent resolver lands.

[Manishearth]

Sounds good, I'll add the rust-version key. I don't really plan on maintaining any MSRV between semver-compat releases, but it doesn't hurt to have the metadata in the Cargo.toml!

[tertsdiepraam]

Not wanting to maintain a policy is very understandable. Thank you!