Bump sentry-rails from 4.6.3 to 4.6.4

Bumps [sentry-rails](https://github.com/getsentry/sentry-ruby) from 4.6.3 to 4.6.4.
- [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/4.6.3...4.6.4)

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

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

Gemfile.lock

@@ -446,7 +446,7 @@ GEM
       childprocess (>= 0.5, < 4.0)
       rubyzip (>= 1.2.2)
     semantic_range (3.0.0)
-    sentry-rails (4.6.3)
+    sentry-rails (4.6.4)
       railties (>= 5.0)
       sentry-ruby-core (~> 4.6.0)
     sentry-ruby (4.6.3)