Bump nokogiri from 1.10.5 to 1.10.6

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.10.5 to 1.10.6.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/master/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.10.5...v1.10.6)

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

Gemfile.lock

@@ -21,7 +21,7 @@ GEM
     json (2.2.0)
     mini_portile2 (2.4.0)
     minitest (5.13.0)
-    nokogiri (1.10.5)
+    nokogiri (1.10.6)
       mini_portile2 (~> 2.4.0)
     rake (13.0.1)
     simplecov (0.16.1)