Upgrade MSRV to Rust 1.69.0

[akainth015]

The GH workflow check is failing with the following error.

error: package `predicates v3.0.4` cannot be built because it requires rustc 1.69.0 or newer, while the currently active rustc version is 1.67.1

This upgrades the MSRV for cargo-watch to Rust 1.69.0, which will allow predicates v3.0.4 to build in CI.

[passcod]

Sorry, no. That version there is the MSRV, and this repo's policy is to have at least five stable versions supported. 1.74.0 is the latest. Fortunately, that means you could change to 1.69.0 and it would be acceptable; you'll also want to change the mention in the Readme and Cargo.toml, though.

[akainth015]

Thank you for pointing me in the right direction.

I have updated README.md, Cargo.toml, and check.yml. I did not find any more references to Rust 1.67.1 in the repository.

[passcod]

Looks like it's failing because of another dependency. Realistically, I'm unlikely to release a new version until the new year, at which point I'll look into these kinds of issues.

Is there a reason you wanted the build to be green?

[akainth015]

Alright, in that case I will close this PR.

I use the build status as an indicator of whether the project is being maintained so I figured it may be helpful to have an accurate build status in the README.