Bumped Rack version to 2.2.3.1

Rack 2.2.3 suffers from 2 CVEs which are fixed in 2.2.3.1: https://github.com/rack/rack/blob/main/CHANGELOG.md#2231---2022-05-27

Signed-off-by: Theo Truong <theotr@amazon.com>

Author: nhtruong

Gemfile.lock

@@ -115,7 +115,7 @@ GEM
     public_suffix (4.0.6)
     racc (1.6.0)
     racc (1.6.0-java)
-    rack (2.2.3)
+    rack (2.2.3.1)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
     rainbow (3.1.1)