docs(README): add information about required gcc version
docs(README): add information about required gcc version

iddar/hiredis-node,BridgeAR/hiredis-node,cmpis/hiredis-node,erulabs/hiredis-node,erulabs/hiredis-node,erulabs/hiredis-node,iddar/hiredis-node,iddar/hiredis-node,BridgeAR/hiredis-node,redis/hiredis-node,redis/hiredis-node,cmpis/hiredis-node,cmpis/hiredis-node,BridgeAR/hiredis-node,redis/hiredis-node