Update hello-world example POM plugin versions

5a21027 (PR #468) bumped the versions of Maven plugins
in PL/Java's actual POMs, but not the versions in the
example POM in the hello-world example. Bump those versions
to match.

Author: jcflack

src/site/markdown/use/hello.md.vm

@@ -119,15 +119,15 @@ individual projects with shorter `pom.xml` files naming this as the parent.
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-compiler-plugin</artifactId>
-        <version>3.8.1</version>
+        <version>3.10.1</version>
         <configuration>
           <release>9</release>
         </configuration>
       </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-jar-plugin</artifactId>
-        <version>2.6</version>
+        <version>3.3.0</version>
         <configuration>
           <archive>
             <manifest>