build(deps-dev): bump tslint from 5.20.1 to 6.1.1 (#302)

build(deps-dev): bump tslint from 5.20.1 to 6.1.1 (#302)

Bumps [tslint](https://github.com/palantir/tslint) from 5.20.1 to 6.1.1.
- [Release notes](https://github.com/palantir/tslint/releases)
- [Changelog](https://github.com/palantir/tslint/blob/master/CHANGELOG.md)
- [Commits](https://github.com/palantir/tslint/compare/5.20.1...6.1.1)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>
Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>