Raise MSRV for embedded-hal-async to Rust 1.65.0

[nospam2678]

Required for generic_associated_types feature.

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @eldruin (or someone else) soon.

Please see the contribution instructions for more information.

[Dirbaio]

Technically embedded-hal-async requires 1.65 because it uses GAT, but it still requires nightly because TAIT. As long as we require nightly, having a MSRV doesn't make much sense.

Could you change it instead to state something along the lines of "requires nightly newer than , but keep in mind nightly can break at any time"?

[nospam2678]

Updated with suggested change to the README file.

As I wrote in the chatroom, I believe setting rust-version might also take a part when cargo performs dependency resolution to determine which crates to use.

One might argue that this PR adds little value, and that's probably true. I didn't realize until now that there are no previous releases, which really makes this PR less valuable than I initially thought catching this in a release candidate would.

For context, the reason for bothering to make it is that the fact that 0.1.0-alpha.2 failed to build while 0.1.0-alpha.1 worked caused a bump in the road for me. The upgrade happened while I was in the process of updating a project with a six+ months outdated embassy. It took a session of trouble shooting that I would want to spare others, if possible.

[bors[bot]]

Build succeeded:

• clippy
• fmt
• test (1.54.0, thumbv6m-none-eabi)
• test (1.54.0, thumbv7m-none-eabi)
• test (1.54.0, x86_64-unknown-linux-gnu)
• test (nightly, thumbv6m-none-eabi)
• test (nightly, thumbv7m-none-eabi)
• test (nightly, x86_64-unknown-linux-gnu)
• test (stable, thumbv6m-none-eabi)
• test (stable, thumbv7m-none-eabi)
• test (stable, x86_64-unknown-linux-gnu)