Bump sentry-rails from 5.5.0 to 5.6.0

Bumps [sentry-rails](https://github.com/getsentry/sentry-ruby) from 5.5.0 to 5.6.0.
- [Release notes](https://github.com/getsentry/sentry-ruby/releases)
- [Changelog](https://github.com/getsentry/sentry-ruby/blob/master/CHANGELOG.md)
- [Commits](https://github.com/getsentry/sentry-ruby/compare/5.5.0...5.6.0)

---
updated-dependencies:
- dependency-name: sentry-rails
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Gemfile.lock

@@ -453,10 +453,10 @@ GEM
       rubyzip (>= 1.2.2, < 3.0)
       websocket (~> 1.0)
     semantic_range (3.0.0)
-    sentry-rails (5.5.0)
+    sentry-rails (5.6.0)
       railties (>= 5.0)
-      sentry-ruby (~> 5.5.0)
-    sentry-ruby (5.5.0)
+      sentry-ruby (~> 5.6.0)
+    sentry-ruby (5.6.0)
       concurrent-ruby (~> 1.0, >= 1.0.2)
     set (1.0.3)
     shakapacker (6.5.4)