amend CI to point to correct rack version

Author: SamSaffron

.github/workflows/ci.yml

@@ -27,7 +27,7 @@ jobs:
       fail-fast: false
       matrix:
         ruby: ["3.4", "3.3", "3.2"]
-        rack: ["2.0", "3.0"]
+        rack: ["2.2", "3.1", "3.2"]
     env:
       RACK_VERSION: ${{ matrix.rack }}
     steps: