Bumps [terser](https://github.com/terser/terser) from 5.1.0 to 5.2.1.
- [Release notes](https://github.com/terser/terser/releases)
- [Changelog](https://github.com/terser/terser/blob/master/CHANGELOG.md)
- [Commits](https://github.com/terser/terser/compare/v5.1.0...v5.2.1)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>