deps(deps): bump heapless from 0.8.0 to 0.9.1

Bumps [heapless](https://github.com/rust-embedded/heapless) from 0.8.0 to 0.9.1.
- [Release notes](https://github.com/rust-embedded/heapless/releases)
- [Changelog](https://github.com/rust-embedded/heapless/blob/main/CHANGELOG.md)
- [Commits](rust-embedded/heapless@v0.8.0...v0.9.1)

---
updated-dependencies:
- dependency-name: heapless
  dependency-version: 0.9.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Cargo.lock

@@ -30,4 +30,4 @@ subtle = { version = "2", default-features = false }
 # Pin to match Hubris ecosystem
 rand_core = { version = "0.9", default-features = false }
 embedded-hal = "1.0"
-heapless = { version = "0.8", default-features = false }
+heapless = { version = "0.9", default-features = false }