cargo: bump bitflags in /src/exercises/bare-metal/rtc in the minor group

Bumps the minor group in /src/exercises/bare-metal/rtc with 1 update: [bitflags](https://github.com/bitflags/bitflags).


Updates `bitflags` from 2.6.0 to 2.8.0
- [Release notes](https://github.com/bitflags/bitflags/releases)
- [Changelog](https://github.com/bitflags/bitflags/blob/main/CHANGELOG.md)
- [Commits](bitflags/bitflags@2.6.0...2.8.0)

---
updated-dependencies:
- dependency-name: bitflags
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: minor
...

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

Author: dependabot[bot]

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

@@ -8,7 +8,7 @@ publish = false
 
 [dependencies]
 arm-gic = "0.1.2"
-bitflags = "2.6.0"
+bitflags = "2.8.0"
 chrono = { version = "0.4.39", default-features = false }
 log = "0.4.22"
 smccc = "0.1.1"