Bump concat-stream from 1.5.1 to 1.6.2 in /web/vtctld2

Bumps [concat-stream](https://github.com/maxogden/concat-stream) from 1.5.1 to 1.6.2.
- [Commits](max-mapper/concat-stream@v1.5.1...v1.6.2)

---
updated-dependencies:
- dependency-name: concat-stream
  dependency-type: indirect
...

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