[Test] Remove unused pom

Author: npofsi

dolphinscheduler-task-plugin/dolphinscheduler-task-grpc/pom.xml

@@ -97,11 +97,6 @@
             <artifactId>grpc-testing</artifactId>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>junit</groupId>
-            <artifactId>junit</artifactId>
-            <scope>test</scope>
-        </dependency>
         <dependency>
             <groupId>com.google.protobuf</groupId>
             <artifactId>protobuf-java</artifactId>