Bump semver and phantomjs

Bumps [semver](https://github.com/npm/node-semver) to 5.7.2 and updates ancestor dependency [phantomjs](https://github.com/Medium/phantomjs). These dependencies need to be updated together.


Updates `semver` from 4.3.6 to 5.7.2
- [Release notes](https://github.com/npm/node-semver/releases)
- [Changelog](https://github.com/npm/node-semver/blob/v5.7.2/CHANGELOG.md)
- [Commits](npm/node-semver@v4.3.6...v5.7.2)

Updates `phantomjs` from 1.9.19 to 1.9.20
- [Release notes](https://github.com/Medium/phantomjs/releases)
- [Commits](Medium/phantomjs@v1.9.19...v1.9.20)

---
updated-dependencies:
- dependency-name: semver
  dependency-type: indirect
- dependency-name: phantomjs
  dependency-type: direct:production
...

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