Bump skylight from 4.1.2 to 4.2.0

Bumps [skylight](https://github.com/skylightio/skylight-ruby) from 4.1.2 to 4.2.0.
- [Release notes](https://github.com/skylightio/skylight-ruby/releases)
- [Changelog](https://github.com/skylightio/skylight-ruby/blob/master/CHANGELOG.md)
- [Commits](skylightio/skylight-ruby@v4.1.2...v4.2.0)

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

Gemfile.lock

@@ -161,7 +161,7 @@ GEM
     mime-types-data (3.2019.0904)
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
-    minitest (5.12.2)
+    minitest (5.13.0)
     multi_xml (0.6.0)
     multipart-post (2.1.1)
     nenv (0.3.0)
@@ -341,9 +341,9 @@ GEM
       json (>= 1.8, < 3)
       simplecov-html (~> 0.10.0)
     simplecov-html (0.10.2)
-    skylight (4.1.2)
-      skylight-core (= 4.1.2)
-    skylight-core (4.1.2)
+    skylight (4.2.0)
+      skylight-core (= 4.2.0)
+    skylight-core (4.2.0)
       activesupport (>= 4.2.0)
     spring (2.1.0)
     spring-watcher-listen (2.0.1)