Bump rack from 2.1.2 to 2.1.4

Bumps [rack](https://github.com/rack/rack) from 2.1.2 to 2.1.4.
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/master/CHANGELOG.md)
- [Commits](rack/rack@2.1.2...2.1.4)

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

Gemfile.lock

@@ -367,7 +367,7 @@ GEM
     public_suffix (4.0.1)
     puma (4.3.5)
       nio4r (~> 2.0)
-    rack (2.1.2)
+    rack (2.1.4)
     rack-protection (2.0.8.1)
       rack
     rack-proxy (0.6.5)