Remove TO_DATE support from roadmap

It's already implemented and working:
https://github.com/h2database/h2database/pull/150

h2/src/docsrc/html/roadmap.html

@@ -117,7 +117,7 @@ See also <a href="build.html#providing_patches">Providing Patches</a>.
 </li><li>Custom class loader to reload functions on demand.
 </li><li>Test http://mysql-je.sourceforge.net/
 </li><li>H2 Console: the webclient could support more features like phpMyAdmin.
-</li><li>Support Oracle functions: TO_DATE, TO_NUMBER.
+</li><li>Support Oracle functions: TO_NUMBER.
 </li><li>Work on the Java to C converter.
 </li><li>The HELP information schema can be directly exposed in the Console.
 </li><li>Maybe use the 0x1234 notation for binary fields, see MS SQL Server.