avro

Bump underscore from 1.12.0 to 1.12.1 in /lang/js

Bumps [underscore](https://github.com/jashkenas/underscore) from 1.12.0 to 1.12.1.
- [Release notes](https://github.com/jashkenas/underscore/releases)
- [Commits](https://github.com/jashkenas/underscore/commits)

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