Bump nokogiri from 1.10.5 to 1.10.8 in /gears/carto_gears_api

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](https://github.com/sparklemotion/nokogiri/compare/v1.10.5...v1.10.8)

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

gears/carto_gears_api/Gemfile.lock

@@ -66,7 +66,7 @@ GEM
     minitest (5.11.3)
     mocha (1.1.0)
       metaclass (~> 0.0.1)
-    nokogiri (1.10.5)
+    nokogiri (1.10.8)
       mini_portile2 (~> 2.4.0)
     pg (0.20.0)
     rack (1.6.12)