fix(deps): [security] bump npm from 6.13.4 to 6.14.6

Bumps [npm](https://github.com/npm/cli) from 6.13.4 to 6.14.6. **This update includes a security fix.**
- [Release notes](https://github.com/npm/cli/releases)
- [Changelog](https://github.com/npm/cli/blob/latest/CHANGELOG.md)
- [Commits](npm/cli@v6.13.4...v6.14.6)

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