Use publish instead of build on Travis
Use publish instead of build on Travis

AppVeyor also does this, and it's the scenario our packages ship, so
it's what we should test.

bmanikm/PowerShell,bmanikm/PowerShell,KarolKaczmarek/PowerShell,daxian-dbw/PowerShell,bingbing8/PowerShell,JamesWTruher/PowerShell-1,kmosher/PowerShell,daxian-dbw/PowerShell,PaulHigin/PowerShell,KarolKaczmarek/PowerShell,PaulHigin/PowerShell,kmosher/PowerShell,bmanikm/PowerShell,TravisEz13/PowerShell,KarolKaczmarek/PowerShell,jsoref/PowerShell,bingbing8/PowerShell,daxian-dbw/PowerShell,TravisEz13/PowerShell,JamesWTruher/PowerShell-1,jsoref/PowerShell,jsoref/PowerShell,PaulHigin/PowerShell,bmanikm/PowerShell,KarolKaczmarek/PowerShell,JamesWTruher/PowerShell-1,bingbing8/PowerShell,kmosher/PowerShell,TravisEz13/PowerShell,kmosher/PowerShell,jsoref/PowerShell,kmosher/PowerShell,bingbing8/PowerShell,KarolKaczmarek/PowerShell,jsoref/PowerShell,TravisEz13/PowerShell,PaulHigin/PowerShell,bingbing8/PowerShell,JamesWTruher/PowerShell-1,daxian-dbw/PowerShell,bmanikm/PowerShell