Use new travis containers
Use new travis containers

eefriedman/serde,jmesmon/serde,serde-rs/serde,csmulhern/serde,skade/serde,sidred10/serde,Hoverbear/serde,tempbottle/serde,JohnHeitmann/serde,3Hren/serde,erickt/serde,infinityb/serde,Ticki/serde,oli-obk/rust-serde,thorbenk/serde