Bump dropshot from 0.12.0 to 0.16.0

Bumps [dropshot](https://github.com/oxidecomputer/dropshot) from 0.12.0 to 0.16.0.
- [Changelog](https://github.com/oxidecomputer/dropshot/blob/main/CHANGELOG.adoc)
- [Commits](oxidecomputer/dropshot@v0.12.0...v0.16.0)

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

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