Bump scout_apm from 2.4.21 to 2.4.24

Bumps [scout_apm](https://github.com/scoutapp/scout_apm_ruby) from 2.4.21 to 2.4.24.
- [Release notes](https://github.com/scoutapp/scout_apm_ruby/releases)
- [Changelog](https://github.com/scoutapp/scout_apm_ruby/blob/master/CHANGELOG.markdown)
- [Commits](scoutapp/scout_apm_ruby@v2.4.21...v2.4.24)

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

Gemfile.lock

@@ -298,7 +298,7 @@ GEM
       sprockets (>= 2.8, < 4.0)
       sprockets-rails (>= 2.0, < 4.0)
       tilt (>= 1.1, < 3)
-    scout_apm (2.4.21)
+    scout_apm (2.4.24)
     sentry-raven (2.9.0)
       faraday (>= 0.7.6, < 1.0)
     sexp_processor (4.11.0)