Merge pull request ra1028#111 from ra1028/dependabot/bundler/Benchmark/json-2.3.1

Bump json from 2.2.0 to 2.3.1 in /Benchmark

Author: ra1028

Benchmark/Gemfile.lock

@@ -56,7 +56,7 @@ GEM
     httpclient (2.8.3)
     i18n (0.9.5)
       concurrent-ruby (~> 1.0)
-    json (2.2.0)
+    json (2.3.1)
     minitest (5.12.2)
     molinillo (0.6.6)
     nanaimo (0.2.6)