Favor additionalOption entries in maven-javadoc-plugin

Cherry-picked from #3231.

Co-authored-by: Jeremy Landis <hazendaz@users.noreply.github.com>

pom.xml

@@ -168,7 +168,10 @@
           <groupId>org.apache.maven.plugins</groupId>
           <artifactId>maven-javadoc-plugin</artifactId>
           <configuration>
-            <additionalOptions>-html5 --allow-script-in-comments</additionalOptions>
+            <additionalOptions>
+              <additionalOption>-html5</additionalOption>
+              <additionalOption>--allow-script-in-comments</additionalOption>
+            </additionalOptions>
             <javadocDirectory>${rootDirectory}/javadoc-theme</javadocDirectory>
             <addStylesheets>
               <stylesheet>assertj-theme.css</stylesheet>