Bump nokogiri from 1.10.5 to 1.10.8

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.10.5 to 1.10.8.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/master/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.10.5...v1.10.8)

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

Gemfile.lock

@@ -95,7 +95,7 @@ GEM
     mini_portile2 (2.4.0)
     minitest (5.11.3)
     nio4r (2.3.1)
-    nokogiri (1.10.5)
+    nokogiri (1.10.8)
       mini_portile2 (~> 2.4.0)
     rack (2.0.8)
     rack-test (1.1.0)