Update page 'Changelog'

Changelog.md

@@ -3,6 +3,7 @@
 - Downloading playlists wont create artist and album folders if options are selected
 - Date tag is now enabled by default on new installations
 - Now users without propic will have a default one in the settings
+- Update message only nags once per client
 - Added space after %explicit% if there is text after the tag
 - Added label at the end of album viewin the modal
 - Fixed forEach error when downloading tracks