Adding license.txt file to csproj as part of code signing compliance.

Forge.TreeWalker/Forge.TreeWalker.csproj

@@ -13,6 +13,7 @@
     <TargetFrameworkVersion>v4.6.2</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
     <Deterministic>true</Deterministic>
+    <PackageLicenseFile>..\LICENSE.txt</PackageLicenseFile>
     <NuGetPackageImportStamp>
     </NuGetPackageImportStamp>
   </PropertyGroup>
@@ -33,6 +34,9 @@
     <ErrorReport>prompt</ErrorReport>
     <WarningLevel>4</WarningLevel>
   </PropertyGroup>
+  <ItemGroup>
+    <None Include="..\LICENSE.txt" Pack="true" PackagePath=""/>
+  </ItemGroup>
   <ItemGroup>
     <Reference Include="System" />
     <Reference Include="System.Collections.Immutable, Version=1.1.37.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">