tests/pkg_relic: increase stacksize
tests/pkg_relic: increase stacksize

ant9000/RIOT,OlegHahm/RIOT,miri64/RIOT,kYc0o/RIOT,kaspar030/RIOT,miri64/RIOT,jasonatran/RIOT,OlegHahm/RIOT,ant9000/RIOT,ant9000/RIOT,OlegHahm/RIOT,miri64/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,ant9000/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,miri64/RIOT,RIOT-OS/RIOT,OlegHahm/RIOT,kaspar030/RIOT,jasonatran/RIOT,ant9000/RIOT,kYc0o/RIOT,jasonatran/RIOT,miri64/RIOT,kYc0o/RIOT,kaspar030/RIOT,kYc0o/RIOT,kaspar030/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,kYc0o/RIOT