Update package to use embedded PackageIcon

Src/Newtonsoft.Json/Newtonsoft.Json.csproj

@@ -18,7 +18,8 @@
     <Title>Json.NET</Title>
     <PackageId>Newtonsoft.Json</PackageId>
     <PackageTags>json</PackageTags>
-    <PackageIconUrl>https://www.newtonsoft.com/content/images/nugeticon.png</PackageIconUrl>
+    <PackageIcon>packageIcon.png</PackageIcon>
+    <PackageIconFullPath>$(MSBuildThisFileDirectory)packageIcon.png</PackageIconFullPath>
     <PackageProjectUrl>https://www.newtonsoft.com/json</PackageProjectUrl>
     <PackageLicenseExpression>MIT</PackageLicenseExpression>
     <PublishRepositoryUrl>true</PublishRepositoryUrl> 
@@ -34,6 +35,7 @@
   <ItemGroup>
     <None Remove="**\*.orig" />
     <None Include="..\..\LICENSE.md" Pack="true" PackagePath="LICENSE.md" />
+    <None Include="$(PackageIconFullPath)" Pack="true" PackagePath="\"/>
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="Microsoft.CodeAnalysis.FxCopAnalyzers" Version="$(MicrosoftCodeAnalysisFxCopAnalyzersPackageVersion)" PrivateAssets="All" />