Bump uglifier from 4.1.9 to 4.1.20
Bump uglifier from 4.1.9 to 4.1.20

Bumps [uglifier](https://github.com/lautis/uglifier) from 4.1.9 to 4.1.20.
- [Release notes](https://github.com/lautis/uglifier/releases)
- [Changelog](https://github.com/lautis/uglifier/blob/master/CHANGELOG.md)
- [Commits](https://github.com/lautis/uglifier/compare/v4.1.9...v4.1.20)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
FundingCircle/shipment_tracker,FundingCircle/shipment_tracker,FundingCircle/shipment_tracker,FundingCircle/shipment_tracker