Bump ciso8601 from 2.3.0 to 2.3.1

Bumps [ciso8601](https://github.com/closeio/ciso8601) from 2.3.0 to 2.3.1.
- [Release notes](https://github.com/closeio/ciso8601/releases)
- [Changelog](https://github.com/closeio/ciso8601/blob/master/CHANGELOG.md)
- [Commits](closeio/ciso8601@v2.3.0...v2.3.1)

---
updated-dependencies:
- dependency-name: ciso8601
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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