Bump underscore from 1.9.1 to 1.13.7 in /web/vtctld2

Bumps [underscore](https://github.com/jashkenas/underscore) from 1.9.1 to 1.13.7.
- [Commits](jashkenas/underscore@1.9.1...1.13.7)

---
updated-dependencies:
- dependency-name: underscore
  dependency-type: indirect
...

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