Bump rake from 12.3.0 to 12.3.1

Bumps [rake](https://github.com/ruby/rake) from 12.3.0 to 12.3.1.
- [Release notes](https://github.com/ruby/rake/releases)
- [Changelog](https://github.com/ruby/rake/blob/master/History.rdoc)
- [Commits](ruby/rake@v12.3.0...v12.3.1)

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

Gemfile.lock

@@ -28,7 +28,7 @@ GEM
       concurrent-ruby (~> 1.0)
     multi_json (1.12.2)
     multi_test (0.1.2)
-    rake (12.3.0)
+    rake (12.3.1)
     rspec-expectations (3.7.0)
       diff-lcs (>= 1.2.0, < 2.0)
       rspec-support (~> 3.7.0)