[Security] Bump nokogiri from 1.10.4 to 1.10.9

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.10.4 to 1.10.9. **This update includes security fixes.**
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/v1.10.9/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.10.4...v1.10.9)

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

Author: dependabot-preview[bot]

Gemfile.lock

@@ -218,7 +218,7 @@ GEM
       jemoji (~> 0.10)
     minitest (5.13.0)
     multipart-post (2.1.1)
-    nokogiri (1.10.7)
+    nokogiri (1.10.9)
       mini_portile2 (~> 2.4.0)
     octokit (4.14.0)
       sawyer (~> 0.8.0, >= 0.5.3)