chore(deps-dev): Bump lerna from 3.19.0 to 3.20.2 (#428)

Bumps [lerna](https://github.com/lerna/lerna/tree/HEAD/core/lerna) from 3.19.0 to 3.20.2.
- [Release notes](https://github.com/lerna/lerna/releases)
- [Changelog](https://github.com/lerna/lerna/blob/master/core/lerna/CHANGELOG.md)
- [Commits](https://github.com/lerna/lerna/commits/v3.20.2/core/lerna)

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