test: upgrade testbench-rpc to 1.4.0

Author: javier-godoy

pom.xml

@@ -128,7 +128,7 @@
 		<dependency>
 			<groupId>com.flowingcode.vaadin.test</groupId>
 			<artifactId>testbench-rpc</artifactId>
-			<version>1.3.0</version>
+			<version>1.4.0</version>
 			<scope>test</scope>
 		</dependency>
 		<dependency>