For buggy/outdated Ruby versions, show links to changelogs

[e2]

If RubyDep detects an outdated/buggy version of Ruby, it could also who links to changelogs or ruby-lang.org posts with information about the given next release. (Next version above what the user has).

Issues:

• I'm not sure if this isn't too complex (e.g. having a full List of Ruby versions seem a bit too extensive - but then again, it wouldn't be that long)
• Changelogs are comprehensive, but hard to read. I guess posts with releases are easier on the eyes, but generating those links can't really be automated (unlike changelogs, which are in SVN).