Bump slug and sonarqube-scanner

Bumps [slug](https://github.com/Trott/slug) and [sonarqube-scanner](https://github.com/bellingard/sonar-scanner-npm). These dependencies needed to be updated together.

Removes `slug`

Updates `sonarqube-scanner` from 0.1.0 to 2.8.1
- [Release notes](https://github.com/bellingard/sonar-scanner-npm/releases)
- [Commits](bellingard/sonar-scanner-npm@0.1.0...2.8.1)

---
updated-dependencies:
- dependency-name: slug
  dependency-type: indirect
- dependency-name: sonarqube-scanner
  dependency-type: direct:development
...

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