Bump skylight from 5.3.4 to 6.0.0

Bumps [skylight](https://github.com/skylightio/skylight-ruby) from 5.3.4 to 6.0.0.
- [Changelog](https://github.com/skylightio/skylight-ruby/blob/master/CHANGELOG.md)
- [Commits](skylightio/skylight-ruby@v5.3.4...v6.0.0)

---
updated-dependencies:
- dependency-name: skylight
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -225,7 +225,7 @@ GEM
     mini_magick (4.12.0)
     mini_mime (1.1.5)
     mini_portile2 (2.8.4)
-    minitest (5.19.0)
+    minitest (5.20.0)
     msgpack (1.7.2)
     multi_json (1.15.0)
     multi_xml (0.6.0)
@@ -429,7 +429,7 @@ GEM
     simplecov-html (0.12.3)
     simplecov-lcov (0.8.0)
     simplecov_json_formatter (0.1.4)
-    skylight (5.3.4)
+    skylight (6.0.0)
       activesupport (>= 5.2.0)
     slop (3.6.0)
     snaky_hash (2.0.1)