Bump nokogiri from 1.8.5 to 1.10.4 in /test-api

Bumps [nokogiri](https://github.com/sparklemotion/nokogiri) from 1.8.5 to 1.10.4.
- [Release notes](https://github.com/sparklemotion/nokogiri/releases)
- [Changelog](https://github.com/sparklemotion/nokogiri/blob/master/CHANGELOG.md)
- [Commits](sparklemotion/nokogiri@v1.8.5...v1.10.4)

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

Author: dependabot[bot]

test-api/Gemfile.lock

@@ -78,12 +78,12 @@ GEM
     method_source (0.9.2)
     mimemagic (0.3.2)
     mini_mime (1.0.1)
-    mini_portile2 (2.3.0)
+    mini_portile2 (2.4.0)
     minitest (5.11.3)
     msgpack (1.2.4)
     nio4r (2.3.1)
-    nokogiri (1.8.5)
-      mini_portile2 (~> 2.3.0)
+    nokogiri (1.10.4)
+      mini_portile2 (~> 2.4.0)
     puma (3.12.0)
     rack (2.0.6)
     rack-cors (1.0.2)