Update package description in composer.json

Added a meaningful description to clarify the purpose of the package. This improves documentation and makes the project more understandable for users.

composer.json

@@ -1,6 +1,6 @@
 {
     "name": "ray/psr-cache-module",
-    "description": "",
+    "description": "PSR-6 PSR-16 cache module for Ray.Di",
     "license": "MIT",
     "authors": [
         {