Update ar-argentina.txt

Final list of 23 players.
[http://www.fifa.com/worldcup/news/y=2014/m=6/news=demichelis-in-argentina-squad-as-trio-miss-out-2353431.html?intcmp=fifacom_hp_module_news]
Merge pull request #16 from zikofv/patch-1

Update ar-argentina.txt