Bump nokogiri from 1.8.1 to 1.8.2

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.8.1 to 1.8.2.
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/master/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.8.1...v1.8.2)

Gemfile.lock

@@ -212,7 +212,7 @@ GEM
       rspec-core (>= 3.4.0, < 3.7.0)
     nenv (0.3.0)
     nio4r (2.1.0)
-    nokogiri (1.8.1)
+    nokogiri (1.8.2)
       mini_portile2 (~> 2.3.0)
     notiffany (0.1.1)
       nenv (~> 0.1)