Bump scout_apm from 5.8.0 to 6.0.0

Bumps [scout_apm](https://github.com/scoutapp/scout_apm_ruby) from 5.8.0 to 6.0.0.
- [Changelog](https://github.com/scoutapp/scout_apm_ruby/blob/master/CHANGELOG.markdown)
- [Commits](https://github.com/scoutapp/scout_apm_ruby/compare/v5.8.0...v6.0.0)

---
updated-dependencies:
- dependency-name: scout_apm
  dependency-version: 6.0.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Gemfile.lock

@@ -689,7 +689,7 @@ GEM
       sprockets (> 3.0)
       sprockets-rails
       tilt
-    scout_apm (5.8.0)
+    scout_apm (6.0.0)
       parser
     searchkick (5.3.1)
       activemodel (>= 6.1)