Bump hyper from 1.8.0 to 1.8.1

Bumps [hyper](https://github.com/hyperium/hyper) from 1.8.0 to 1.8.1.
- [Release notes](https://github.com/hyperium/hyper/releases)
- [Changelog](https://github.com/hyperium/hyper/blob/master/CHANGELOG.md)
- [Commits](hyperium/hyper@v1.8.0...v1.8.1)

---
updated-dependencies:
- dependency-name: hyper
  dependency-version: 1.8.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Author: dependabot[bot]