chore(deps+cargo)(deps): bump serialport from 4.8.1 to 4.9.0

[dependabot]

Bumps serialport from 4.8.1 to 4.9.0.

Changelog

Sourced from serialport's changelog.

[4.9.0] -- 2026-03-12

Changed

• Enumerate serial-base subsystem on Linux without libudev support too. Some of these newly enumerated ports may show up with a different type than with libudev, but they will be finally enumerated at all. #311
• Enable arbitrary baud rates for Linux musl targets by directly using termios2 and the corresponding ioctls TCGETS2 and TCSETS2 from nix and the libc crate. There is no support form musl for termios2 and we are directly talking to the kernel and bypassing it here. #316

Fixed

• Always propagate errors out of termios getter/setter implementations.
• Wrap slave port file descriptors in TTYPort::pair in a Drop-safe OwnedFd to avoid file descriptor leaks on early returns.
• Enable arbitrary baud rates for Linux musl targets by using the termios2 (TCGETS2/TCSETS2 + BOTHER) path now that required libc symbols are available. #316
• Unpin dependencies with MSRV incompatible Rust version bump. This caused issues with dependency resolution for many users building with newer Rust versions. See Dependencies on how to pin them in your project when building with older Rust versions. #324 #307 #304 #300 #231

Commits

• 2a62b22 Release 4.9.0
• 6b89d13 Add changelog for unpinning dependencies
• 6055cdf Add note on dependency pinning to README.md
• 9127852 Just pin dependencies for MSRV builds in CI
• 1e451a0 Clean up minor Clippy issues for BSD
• 5fd01f8 Run Clippy for selected and all features in CI
• 69edbed Don't install system deps for fmt checks
• 4fd7818 Clean up indentation for CI semver checks
• 349f9ac Move TODO comments in ci.yaml out of the way
• be5867a Run Clippy for multiple targets
• Additional commits viewable in compare view

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