Bump eslint and eslint-config-xo-space (#143)

Bumps [eslint](https://github.com/eslint/eslint) and [eslint-config-xo-space](https://github.com/xojs/eslint-config-xo-space). These dependencies needed to be updated together.

Updates `eslint` from 5.16.0 to 6.6.0
- [Release notes](https://github.com/eslint/eslint/releases)
- [Changelog](https://github.com/eslint/eslint/blob/master/CHANGELOG.md)
- [Commits](eslint/eslint@v5.16.0...v6.6.0)

Updates `eslint-config-xo-space` from 0.21.0 to 0.22.0
- [Release notes](https://github.com/xojs/eslint-config-xo-space/releases)
- [Commits](xojs/eslint-config-xo-space@v0.21.0...v0.22.0)

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