Add Javadoc link specific to version 2.3.0.
<item name="Javadoc (2.1 release)" href="/api-2.1/index.html"/>
<item name="Javadoc (2.1.1 release)" href="/api-2.1.1/index.html"/>
<item name="Javadoc (2.2.0 release)" href="/api-2.2.0/index.html"/>
+ <item name="Javadoc (2.3.0 release)" href="/api-2.3.0/index.html"/>
<item name="Developers&#xA0;Guide" href="/guide/index.html" collapse="true">
<item name="JNDI&#xA0;Howto" href="/guide/jndi-howto.html"/>
<item name="Class&#xA0;Diagrams" href="/guide/classdiagrams.html"/>
