build(deps): bump gatsby-plugin-theme-ui from 0.16.2 to 0.17.1 (#85)

Bumps [gatsby-plugin-theme-ui](https://github.com/system-ui/theme-ui) from 0.16.2 to 0.17.1.
- [Release notes](https://github.com/system-ui/theme-ui/releases)
- [Changelog](https://github.com/system-ui/theme-ui/blob/v0.17.1/CHANGELOG.md)
- [Commits](system-ui/theme-ui@v0.16.2...v0.17.1)

---
updated-dependencies:
- dependency-name: gatsby-plugin-theme-ui
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>