chore(deps): bump icalendar from 0.16.0 to 0.16.8

Bumps [icalendar](https://github.com/hoodie/icalendar-rs) from 0.16.0 to 0.16.8.
- [Release notes](https://github.com/hoodie/icalendar-rs/releases)
- [Changelog](https://github.com/hoodie/icalendar-rs/blob/main/CHANGELOG.md)
- [Commits](hoodie/icalendar@v0.16.0...v0.16.8)

---
updated-dependencies:
- dependency-name: icalendar
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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