Create an issue to request an abandoned plugin to be updated by Poggit Orphanage.
If you have updated an old plugin but only made very minor changes (no major rewrite/additions), you must release it through Poggit Orphanage too (create an issue with a link to your updated version); do not submit the plugin to Poggit directly. (If you made major changes, you may release it directly with sufficient credit in the "Authors" entry in the submit form)