Expected Behavior

.net 4.8 is out, and would like to have psake support builds with the same

Current Behavior

currently there is support for upto .net 4.7.2

Possible Solution

PR attached.
added 4.8 to list of supported frameworks, with msbuild 15.0

Context

We currently use psake for build scripting, and are looking to upgrade to .net 4.8
however, we only can upgrade to .net 4.7.2

Your Environment

• Module version used:
• Operating System and PowerShell version: