Merge pull request #3312 from rails/dependabot/bundler/rack-2.2.6.4

Bump rack from 2.2.6.2 to 2.2.6.4

Author: amatsuda

Gemfile.lock

@@ -97,7 +97,7 @@ GEM
     parser (3.0.2.0)
       ast (~> 2.4.1)
     racc (1.6.2)
-    rack (2.2.6.2)
+    rack (2.2.6.4)
     rack-proxy (0.7.0)
       rack
     rack-test (1.1.0)