Bump underscore from 1.12.0 to 1.13.6

Bumps [underscore](https://github.com/jashkenas/underscore) from 1.12.0 to 1.13.6.
- [Release notes](https://github.com/jashkenas/underscore/releases)
- [Commits](jashkenas/underscore@1.12.0...1.13.6)

---
updated-dependencies:
- dependency-name: underscore
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>