fix valkey's image name in CI

Author: amirreza8002

.github/workflows/ci.yml

@@ -59,14 +59,14 @@ jobs:
             valkey: 'latest'
           - os: ubuntu
             pyver: '3.9'
-            valkey: '5.0.14'
+            valkey: '7.2.8'
           - os: ubuntu
             pyver: '3.9'
             valkey: 'latest'
             ujson: 'ujson'
     services:
       valkey:
-        image: valkey:${{ matrix.valkey }}
+        image: valkey/valkey:${{ matrix.valkey }}
         ports:
         - 6379:6379
         options: >-