Update cantarell font in 16.04 repo

[Jonatan H. Zeidler]

Hi there,

I hope this is the right place for this request. There is an annoying 
bug in the Ubuntu GNOME default font Cantarell (package fonts-cantarell, 
version 0.0.21-1) that effects various letters. One of them is the Ü, 
which is important in German. The issue is solved in the 16.10 repo 
(0.0.24-1).

As Ubuntu GNOME 16.04 is a LTS version that is going to be used for 
years I suggest to put the never version that is already in the 16.10 
into the 16.04 repo, if possible. I consider this kind of critical for 
German users. Here you can find the bug report: 
https://bugzilla.gnome.org/show_bug.cgi?id=767604

Thanks for your great work!

Regards
Jonius