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.
- [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)

Author: dependabot[bot]

Gemfile.lock

@@ -61,7 +61,7 @@ GEM
     mercenary (0.3.6)
     mini_portile2 (2.3.0)
     minitest (5.11.3)
-    nokogiri (1.8.4)
+    nokogiri (1.8.5)
       mini_portile2 (~> 2.3.0)
     parallel (1.12.1)
     pathutil (0.16.1)