Bump rollbar from 3.4.2 to 3.5.1

Bumps [rollbar](https://github.com/rollbar/rollbar-gem) from 3.4.2 to 3.5.1.
- [Release notes](https://github.com/rollbar/rollbar-gem/releases)
- [Changelog](https://github.com/rollbar/rollbar-gem/blob/master/CHANGELOG.md)
- [Commits](rollbar/rollbar-gem@v3.4.2...v3.5.1)

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

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

Gemfile.lock

@@ -495,7 +495,7 @@ GEM
       mime-types (>= 1.16, < 4.0)
       netrc (~> 0.8)
     rexml (3.2.6)
-    rollbar (3.4.2)
+    rollbar (3.5.1)
     rspec-core (3.12.2)
       rspec-support (~> 3.12.0)
     rspec-expectations (3.12.3)