Bump semver from 1.0.5 to 1.0.6

Bumps [semver](https://github.com/dtolnay/semver) from 1.0.5 to 1.0.6.
- [Release notes](https://github.com/dtolnay/semver/releases)
- [Commits](https://github.com/dtolnay/semver/compare/1.0.5...1.0.6)

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

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