Just found via Twitter thanks to Matt Hawley: SubversionFeed.

This service takes any SVN repository with anonymous access enabled and transforms it into a RSS feed with the latest 10 changes.

I just subscribed to Subtext SVN RSS feed:
http://svnfeed.com/convert?url=https%3A%2F%2Fsubtext.svn.sourceforge.net%2Fsvnroot%2Fsubtext