New location for Microsoft.Web.Publishing.Tasks.dll with Visual Studio 2017

[dsschnau]

Hello,

I found out today while migrating to a new build server with only Visual Studio 2017 installed that the dependency on Microsoft.Web.Publishing.Tasks.dll broke on our gulp-config-transform task. After investigating I found that the location for this .dll has changed and no longer is automatically located.

For our immediate need, I'm going to update our gulp config accordingly, but would it be worthwhile to make a PR to add the new location?

(btw, the new location is C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild\Microsoft\VisualStudio\v15.0\Web via the Release Notes for msbuild 15)