Fix README.md typo.
Fix README.md typo.

asoesilo/angular-pickadate,restorando/angular-pickadate,iOffice/angular-pickadate,joohyuntae/puredatepicker,BleeveNL/angular-pickadate,Menjoy/angular-pickadate,Menjoy/angular-pickadate,Studio133/angular-pickadate,joohyuntae/puredatepicker,startappdev/angular-pickadate,startappdev/angular-pickadate,tanz-sullamora/angular-pickadate,fontenele/angular-pickadate