Feed plugin creates a new version of the feed document every time it updates the concerned feed

When updating a feed, the feed plugin write the date of latest update in the feed document, thus generating a new version. This is not good as such docs will quickly end with a very large number of versions ; and this will affect the behavior of history viewing, or deletion raising java.lang.OutOfMemoryError: Java heap space.

see com.xpn.xwiki.plugin.feed.FeedPlugin#updateFeeds(String, boolean, boolean, boolean, String, XWikiContext).