include alpha in the generate nightly package version
i don't know which logic nuget uses to detect pre-release
so it's safer to include alpha in the nightly build version.
this is intended to create nightly build with package
versions of the form x.y.z-yyyyMMdd.sha and
push them to nuget automatically, only where there
are new changes per day. since devops is a nightmare
and entirely untestable we will have to go through 20
iterations to actually get this to work
