Bump spin from 0.9.6 to 0.9.8 in /src/exercises/bare-metal/rtc (#543)

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: direct:production
...

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

src/exercises/bare-metal/rtc/Cargo.lock

@@ -100,9 +100,9 @@ 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",
 ]

src/exercises/bare-metal/rtc/Cargo.toml

@@ -11,7 +11,7 @@ bitflags = "2.0.0"
 chrono = { version = "0.4.24", default-features = false }
 log = "0.4.17"
 psci = "0.1.1"
-spin = "0.9.4"
+spin = "0.9.8"
 
 [build-dependencies]
 cc = "1.0.73"