Update README.md

Author: VirtueSky

README.md

@@ -25,7 +25,7 @@
 ### Add the line below to `Packages/manifest.json`
 
 for version `1.0.1`
-```csharp
+```json
 "com.wolf-org.object-pooling":"https://github.com/unity-package/object-pooling-unity.git#1.0.1",
 ```
 ## Use