Bump rack from 2.2.1 to 2.2.3

Bumps [rack](https://github.com/rack/rack) from 2.2.1 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@v2.2.1...2.2.3)

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

Author: dependabot[bot]

Gemfile.lock

@@ -86,7 +86,7 @@ GEM
     nio4r (2.5.2)
     nokogiri (1.10.8)
       mini_portile2 (~> 2.4.0)
-    rack (2.2.1)
+    rack (2.2.3)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
     rails (6.0.2.1)