chore: Bump msrv to 1.70

[tottoto]

home 0.5.9 requires Rust 1.70.

[caspermeijn]

Can you give more context why you think this is needed?

For me, cargo msrv verify reports the MSRV is correct.

$ cargo msrv verify
Fetching index
Verifying the Minimum Supported Rust Version (MSRV) for toolchain x86_64-unknown-linux-gnu
Using check command cargo check
   Finished Satisfied MSRV check: 1.60.0

[caspermeijn]

This PR can be closed as the issue is fixed in #982

[tottoto]

Are there any reason to bump the msrv of the crates which do not depend on home?

[caspermeijn]

It feels like there is too little maintainer capacity, and I think a single MSRV for the whole repo is easier to maintain. This PR doesn't actually verify the MSRV of main prost crate in CI.

[tottoto]

This PR doesn't actually verify the MSRV of main prost crate in CI.

Yes, and it has not been performed in this project as well so far.

Bumping the rust-version field make build fail the build lower than its version (without --ignore-rust-version option), and as prost is a widely used crate, it effect is relatively large.

[caspermeijn]

Let's continue this discussion in #983