[Security] Bump nokogiri from 1.8.4 to 1.8.5

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.8.4 to 1.8.5. **This update includes security fixes.**
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/master/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.8.4...v1.8.5)

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

Gemfile.lock

@@ -149,7 +149,7 @@ GEM
  mustermann (1.0.3)
  nenv (0.3.0)
  nio4r (2.3.1)
- nokogiri (1.8.4)
+ nokogiri (1.8.5)
  mini_portile2 (~> 2.3.0)
  notiffany (0.1.1)
  nenv (~> 0.1)