Use .NET 3.0 in Local.props.example

As of bug25552, it's the new minimum required version.

Author: michaelklishin

Local.props.example

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="3.5" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
-    <PropTargetFramework>v3.5</PropTargetFramework>
+    <PropTargetFramework>v3.0</PropTargetFramework>
     <PropAssemblyVersion>0.0.0.0</PropAssemblyVersion>
     <PropUsingMono>false</PropUsingMono>