build(deps): bump config from 5.5.1 to 5.5.2

Bumps [config](https://github.com/rubyconfig/config) from 5.5.1 to 5.5.2.
- [Release notes](https://github.com/rubyconfig/config/releases)
- [Changelog](https://github.com/rubyconfig/config/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rubyconfig/config/commits/5.5.2)

---
updated-dependencies:
- dependency-name: config
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Gemfile.lock

@@ -125,8 +125,9 @@ GEM
       matrix
       ruby-rc4 (>= 0.1.5)
     concurrent-ruby (1.3.4)
-    config (5.5.1)
+    config (5.5.2)
       deep_merge (~> 1.2, >= 1.2.1)
+      ostruct
     connection_pool (2.4.1)
     cookies_eu (1.7.8)
       js_cookie_rails (~> 2.2.0)
@@ -272,6 +273,7 @@ GEM
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
     observer (0.1.2)
+    ostruct (0.6.0)
     parser (3.3.2.0)
       ast (~> 2.4.1)
       racc