update help output to include available tasks
update help output to include available tasks

zugolosian/relx,bitwalker/relx,priestjim/relx,umatomba/relx,erlware/relx,bsmr-erlang/relx,ethercrow/relx,lrascao/relx,timclassic/relx,tsloughter/relx,ingwinlu/relx,Licenser/relx,RJ/relx