Follow latest Rails allowed rubies

Author: dhh

.github/workflows/ci.yml

@@ -6,7 +6,7 @@ jobs:
     strategy:
       matrix:
         redis_server: ["4", "5", "6", "7"]
-        ruby: ["2.7", "3.0", "3.1", "3.2"]
+        ruby: ["3.1", "3.2", "3.3"]
 
     name: Redis server ${{ matrix.redis_server }} - Ruby ${{ matrix.ruby }}