build(deps-dev): bump zest-releaser from 7.3.0 to 8.0.0

Bumps [zest-releaser](https://github.com/zestsoftware/zest.releaser) from 7.3.0 to 8.0.0.
- [Changelog](https://github.com/zestsoftware/zest.releaser/blob/master/CHANGES.rst)
- [Commits](zestsoftware/zest.releaser@7.3.0...8.0.0)

---
updated-dependencies:
- dependency-name: zest-releaser
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>