adding NuGet logo and README support (#5183)

* adding NuGet logo and README support

* fixed MSBuild variables

* fixed version

src/common.props

@@ -3,10 +3,11 @@
     <Copyright>Copyright © 2013-2021 Akka.NET Team</Copyright>
     <Authors>Akka.NET Team</Authors>
     <VersionPrefix>1.4.28</VersionPrefix>
-    <PackageIconUrl>https://getakka.net/images/akkalogo.png</PackageIconUrl>
+    <PackageIcon>akkalogo.png</PackageIcon>
     <PackageProjectUrl>https://github.com/akkadotnet/akka.net</PackageProjectUrl>
     <PackageLicenseUrl>https://github.com/akkadotnet/akka.net/blob/master/LICENSE</PackageLicenseUrl>
     <NoWarn>$(NoWarn);CS1591;xUnit1013</NoWarn>
+    <PackageReadmeFile>README.md</PackageReadmeFile>
   </PropertyGroup>
   <PropertyGroup>
     <XunitVersion>2.4.1</XunitVersion>
@@ -37,6 +38,10 @@
   <ItemGroup>
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0" PrivateAssets="All" />
   </ItemGroup>
+  <ItemGroup>
+    <None Include="$(MSBuildThisFileDirectory)\..\docs\images\akkalogo.png" Pack="true" Visible="false" PackagePath="\" />
+    <None Include="$(MSBuildThisFileDirectory)\..\README.md" Pack="true" Visible="false" PackagePath="\" />
+  </ItemGroup>
   <PropertyGroup>
     <!--<PublishRepositoryUrl>true</PublishRepositoryUrl>-->
     <RepositoryUrl>https://github.com/akkadotnet/akka.net</RepositoryUrl>
@@ -46,4 +51,8 @@
     <IncludeSymbols>true</IncludeSymbols>
     <SymbolPackageFormat>snupkg</SymbolPackageFormat>
   </PropertyGroup>
-</Project>
+    <Target Name="TestValue" AfterTargets="build">
+    <Message Text="@(none)">
+    </Message>
+  </Target>
+</Project>