build(deps): bump drb from 2.1.1 to 2.2.0

Bumps [drb](https://github.com/ruby/drb) from 2.1.1 to 2.2.0.
- [Release notes](https://github.com/ruby/drb/releases)
- [Commits](ruby/drb@v2.1.1...v2.2.0)

---
updated-dependencies:
- dependency-name: drb
  dependency-type: indirect
  update-type: version-update:semver-minor
...

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

Gemfile.lock

@@ -112,7 +112,7 @@ GEM
       sass-embedded (~> 1.63)
     date (3.3.3)
     docile (1.4.0)
-    drb (2.1.1)
+    drb (2.2.0)
       ruby2_keywords
     erb_lint (0.5.0)
       activesupport