Bump heapless from 0.8.0 to 0.9.1 (#976)

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]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Cargo.lock

@@ -10,7 +10,7 @@ readme.workspace = true
 description = """Provides the tracing functionality for the hyperlight guest."""
 
 [dependencies]
-heapless = { version = "0.8.0", features = ["serde"] }
+heapless = { version = "0.9.1", features = ["serde"] }
 hyperlight-common = { workspace = true, default-features = false }
 spin = "0.10.0"
 tracing = { version = "0.1.41", default-features = false, features = ["attributes"] }