just figured out what to do myself, mind you this may not be 100% the best way
go into trinity > variables
open trinity variable configuration
Barbarian.Warcry.Maxfury set this to 200
SpellsDelay.Barbarian_warcry i have mine set to 17000 but you could work out your cooldown for warcry in millisecs(after cd reduction) and enter that
after this the bot seems to spam it, hopefully this helps