Address some warnings in maven execution

pom.xml

@@ -481,7 +481,16 @@
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-dependency-plugin</artifactId>
-        <version>3.7.1</version>
+        <version>3.8.1</version>
+        <executions>
+          <execution>
+            <!-- Set dependencies as properties for use in argLine property for mockito jar -->
+            <goals>
+              <goal>properties</goal>
+            </goals>
+          </execution>
+        </executions>
+
       </plugin>
 
       <plugin>

service/pom.xml

@@ -698,8 +698,8 @@
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-surefire-plugin</artifactId>
         <configuration>
-          <!-- work around PATCH not being a supported method on HttpUrlConnection -->
-          <argLine>--add-opens=java.base/java.net=ALL-UNNAMED</argLine>
+          <!-- add-opens: work around PATCH not being a supported method on HttpUrlConnection -->
+          <argLine>-javaagent:${org.mockito:mockito-core:jar} --add-opens=java.base/java.net=ALL-UNNAMED</argLine>
         </configuration>
       </plugin>
 

websocket-resources/pom.xml

@@ -101,6 +101,23 @@
       <artifactId>junit-jupiter</artifactId>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-core</artifactId>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <configuration>
+          <argLine>-javaagent:${org.mockito:mockito-core:jar}</argLine>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+
 </project>