Bump benchmark from 0.3.0 to 0.4.0

Bumps [benchmark](https://github.com/ruby/benchmark) from 0.3.0 to 0.4.0.
- [Release notes](https://github.com/ruby/benchmark/releases)
- [Commits](ruby/benchmark@v0.3.0...v0.4.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -8,7 +8,7 @@ GEM
   remote: https://rubygems.org/
   specs:
     ast (2.4.2)
-    benchmark (0.3.0)
+    benchmark (0.4.0)
     coderay (1.1.3)
     concurrent-ruby (1.3.4)
     docile (1.4.0)