Add mockito-core javaagent for future Java compatibility

https://javadoc.io/doc/org.mockito/mockito-core/latest/org/mockito/Mockito.html#0.3
warns that Java version 21 and later report a warning when trying to
use Mockito without the javaagent. Followed the instructions in their
documentation to add mockito javaagent.

Author: MarkEWaite

pom.xml

@@ -291,13 +291,28 @@
 
   <build>
     <plugins>
+      <plugin>
+        <!-- Needed by the mockito-core properties reference in surefire -->
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-dependency-plugin</artifactId>
+        <executions>
+          <execution>
+            <goals>
+              <goal>properties</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-surefire-plugin</artifactId>
         <configuration>
           <systemPropertyVariables>
             <org.jenkinsci.plugins.gitclient.verifier.SshHostKeyVerificationStrategy.jgit_known_hosts_file>${project.build.directory}/ssh/know_hosts</org.jenkinsci.plugins.gitclient.verifier.SshHostKeyVerificationStrategy.jgit_known_hosts_file>
           </systemPropertyVariables>
+          <!-- Add mockito javaagent for the MockitoJUnitRunner in Java 21 and beyond -->
+          <!-- https://javadoc.io/doc/org.mockito/mockito-core/latest/org/mockito/Mockito.html#0.3 -->
+          <argLine>@{argLine} -javaagent:${org.mockito:mockito-core:jar}</argLine>
         </configuration>
       </plugin>
       <plugin>