Added grpc-testing dependency

Signed-off-by: MMaiero <matteo.maiero@eurotech.com>

Author: MMaiero

kura/test/org.eclipse.kura.ai.triton.server.test/pom.xml

@@ -41,6 +41,12 @@
             <version>${grpc.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>io.grpc</groupId>
+            <artifactId>grpc-testing</artifactId>
+            <version>${grpc.version}</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
     <build>