[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] <[email protected]>

Author: dependabot-support

Gemfile.lock

@@ -215,7 +215,7 @@ GEM
       jekyll-seo-tag (~> 2.1)
     minitest (5.11.3)
     multipart-post (2.0.0)
-    nokogiri (1.8.4)
+    nokogiri (1.8.5)
       mini_portile2 (~> 2.3.0)
     octokit (4.11.0)
       sawyer (~> 0.8.0, >= 0.5.3)