Update RSocketAdvice.java

Author: SentryMan

src/main/java/com/mangasite/rsocket/RSocketAdvice.java

@@ -6,8 +6,10 @@
 
 import io.rsocket.exceptions.CustomRSocketException;
 import io.rsocket.exceptions.RejectedException;
+import jakarta.inject.Singleton;
 import reactor.core.publisher.Mono;
 
+@Singleton
 @ControllerAdvice
 public class RSocketAdvice {