build(deps): bump tar and npm

Removes [tar](https://github.com/npm/node-tar). It's no longer used after updating ancestor dependency [npm](https://github.com/npm/cli). These dependencies need to be updated together.


Removes `tar`

Updates `npm` from 7.16.0 to 7.20.6
- [Release notes](https://github.com/npm/cli/releases)
- [Changelog](https://github.com/npm/cli/blob/v7.20.6/CHANGELOG.md)
- [Commits](npm/cli@v7.16.0...v7.20.6)

---
updated-dependencies:
- dependency-name: tar
  dependency-type: indirect
- dependency-name: npm
  dependency-type: indirect
...

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