Rev build task version per day

[agocke]

When we release nuget packages for the compiler with a new build task that task may not be loaded because the task with the same assembly version may have already been loaded with a different path.

If we Rev the minor version every day (by including the date in the version number) then installing various versions of the compiler should be fine as long s they weren't built in the exact same day.

[asvishnyakov]

Incrementing?

[ghost]

+1 on just increment the minor version following the semver convention. Doesn't matter if we end up having 4.20.5008, it is still a valid plain semantic version.