Bump hawk, coveralls, karma-coveralls and phantomjs-prebuilt

Removes [hawk](https://github.com/mozilla/hawk). It's no longer used after updating ancestor dependencies [hawk](https://github.com/mozilla/hawk), [coveralls](https://github.com/nickmerwin/node-coveralls), [karma-coveralls](https://github.com/caitp/karma-coveralls) and [phantomjs-prebuilt](https://github.com/Medium/phantomjs). These dependencies need to be updated together.


Removes `hawk`

Updates `coveralls` from 2.11.15 to 3.1.1
- [Release notes](https://github.com/nickmerwin/node-coveralls/releases)
- [Commits](https://github.com/nickmerwin/node-coveralls/commits/3.1.1)

Updates `karma-coveralls` from 1.1.2 to 1.2.1
- [Release notes](https://github.com/caitp/karma-coveralls/releases)
- [Commits](https://github.com/caitp/karma-coveralls/commits)

Updates `phantomjs-prebuilt` from 2.1.14 to 2.1.16
- [Release notes](https://github.com/Medium/phantomjs/releases)
- [Commits](https://github.com/Medium/phantomjs/commits)

---
updated-dependencies:
- dependency-name: hawk
  dependency-type: indirect
- dependency-name: coveralls
  dependency-type: direct:development
- dependency-name: karma-coveralls
  dependency-type: direct:development
- dependency-name: phantomjs-prebuilt
  dependency-type: direct:development
...

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

Author: dependabot[bot]