[triggers] Update manifest.ini

triggers/manifest.ini

 [info]
 name: Triggers
 short_name: triggers
-version: 0.4
+version: 0.5
 description: Configure Gajim's behaviour for each contact
 authors: Yann Leboulanger <asterix@lagaule.org>
 homepage: https://dev.gajim.org/gajim/gajim-plugins/wikis/TriggersPlugin