Microsoft.FSharp.targets or Microsoft.FSharp.Targets

Removed old file, same filename different case.
That is a problem with git and case insensitive filesystem (osx/win)

the correct case is Microsoft.FSharp.targets or Microsoft.FSharp.Targets ?
fast search show few point with lowercase .targets, and 3.0 was .Targets.

I can easy update this pr with rename and replace usage