Selenium Grid error no main manifest attribute, in selenium-server-4.0.0-alpha-2.jar

I am trying to set up Selenium hub and I am getting this error.

no main manifest attribute, in selenium-server-4.0.0-alpha-2.jar

java -jar selenium-server-4.0.0-alpha-2.jar -role hub

In Maven I have the correct plugin in POM already. What else could be the issue?

<plugin>
   <groupId>org.apache.maven.plugins</groupId>
   <artifactId>maven-jar-plugin</artifactId>
   <configuration>
      <archive>
         <manifest>
            <mainClass>com.abc.qr.xyz.MainClass</mainClass>
         </manifest>
      </archive>
   </configuration>
</plugin>