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

@@ -8,11 +8,11 @@ GEM
       semver2 (~> 3.4)
     map (6.6.0)
     mini_portile2 (2.4.0)
-    nokogiri (1.10.5)
+    nokogiri (1.10.8)
       mini_portile2 (~> 2.4.0)
-    nokogiri (1.10.5-x64-mingw32)
+    nokogiri (1.10.8-x64-mingw32)
       mini_portile2 (~> 2.4.0)
-    nokogiri (1.10.5-x86-mingw32)
+    nokogiri (1.10.8-x86-mingw32)
       mini_portile2 (~> 2.4.0)
     rake (10.5.0)
     semver2 (3.4.2)