Bump rack from 2.0.8 to 2.2.3

Bumps [rack](https://github.com/rack/rack) from 2.0.8 to 2.2.3.
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/master/CHANGELOG.md)
- [Commits](rack/rack@2.0.8...2.2.3)

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

Author: dependabot[bot]

Gemfile.lock

@@ -17,7 +17,7 @@ GEM
       mini_portile2 (~> 2.4.0)
     pygments.rb (1.2.1)
       multi_json (>= 1.0.0)
-    rack (2.0.8)
+    rack (2.2.3)
     rake (12.3.3)
     yajl-ruby (1.4.1)