Bump spin from 0.9.6 to 0.9.8 in /src/bare-metal/alloc-example (#544)

Bumps [spin](https://github.com/mvdnes/spin-rs) from 0.9.6 to 0.9.8.
- [Release notes](https://github.com/mvdnes/spin-rs/releases)
- [Changelog](https://github.com/mvdnes/spin-rs/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mvdnes/spin-rs/commits)

---
updated-dependencies:
- dependency-name: spin
  dependency-type: indirect
...

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

src/bare-metal/alloc-example/Cargo.lock

@@ -49,9 +49,9 @@ checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
 
 [[package]]
 name = "spin"
-version = "0.9.6"
+version = "0.9.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5d6e0250b93c8427a177b849d144a96d5acc57006149479403d7861ab721e34"
+checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
 dependencies = [
  "lock_api",
 ]