refactor: Reduce visibility of package

Author: TimothyJones

src/main/java/io/contract_testing/contractcase/client/RpcConnector.java

@@ -23,7 +23,7 @@
 import java.util.concurrent.atomic.AtomicInteger;
 import org.jetbrains.annotations.NotNull;
 
-public class RpcConnector {
+class RpcConnector {
 
   private static final int DEFAULT_PORT = 50200;