Update GitVersioning NuGet (#68)

***NO_CI***

Author: josesimoes

source/nanoFramework.CoreLibrary/CoreLibrary.nfproj

@@ -376,12 +376,19 @@
   </ItemGroup>
   <ItemGroup>
     <None Include="..\key.snk" />
+    <None Include="packages.config" />
   </ItemGroup>
   <Import Project="$(NanoFrameworkProjectSystemPath)NFProjectSystem.CSharp.targets" Condition="Exists('$(NanoFrameworkProjectSystemPath)NFProjectSystem.CSharp.targets')" />
-  <Import Project="..\packages\Nerdbank.GitVersioning.2.3.34\build\Nerdbank.GitVersioning.targets" />
   <ProjectExtensions>
     <ProjectCapabilities>
       <ProjectConfigurationsDeclaredAsItems />
     </ProjectCapabilities>
   </ProjectExtensions>
+  <Import Project="..\packages\Nerdbank.GitVersioning.3.0.6-beta\build\Nerdbank.GitVersioning.targets" Condition="Exists('..\packages\Nerdbank.GitVersioning.3.0.6-beta\build\Nerdbank.GitVersioning.targets')" />
+  <Target Name="EnsureNuGetPackageBuildImports" BeforeTargets="PrepareForBuild">
+    <PropertyGroup>
+      <ErrorText>This project references NuGet package(s) that are missing on this computer. Enable NuGet Package Restore to download them.  For more information, see http://go.microsoft.com/fwlink/?LinkID=322105.The missing file is {0}.</ErrorText>
+    </PropertyGroup>
+    <Error Condition="!Exists('..\packages\Nerdbank.GitVersioning.3.0.6-beta\build\Nerdbank.GitVersioning.targets')" Text="$([System.String]::Format('$(ErrorText)', '..\packages\Nerdbank.GitVersioning.3.0.6-beta\build\Nerdbank.GitVersioning.targets'))" />
+  </Target>
 </Project>

source/nanoFramework.CoreLibrary/packages.config

@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="Nerdbank.GitVersioning" version="2.3.34" developmentDependency="true" />
+  <package id="Nerdbank.GitVersioning" version="3.0.6-beta" developmentDependency="true" />
 </packages>