add news item for ikiwiki 3.20121212

[ikiwiki] / doc / news / version_3.20121212.mdwn

ikiwiki 3.20121212 released with [[!toggle text="these changes"]]
[[!toggleable text="""
   * filecheck: Fix bug that prevented File::MimeInfo::Magic from ever
     being used.
   * openid: Display openid in Preferences page as a comment, so it can be
     selected in all browsers."""]]