Updates the requirements on [tock-registers](https://github.com/tock/tock) to permit the latest version.
- [Release notes](https://github.com/tock/tock/releases)
- [Changelog](https://github.com/tock/tock/blob/master/CHANGELOG.md)
- [Commits](https://github.com/tock/tock/commits/tock-registers-v0.8

)

---
updated-dependencies:
- dependency-name: tock-registers
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>