Update icon url and use package licence expression

Author: Oren Novotny

Rx.NET/Source/Directory.build.props

@@ -5,9 +5,9 @@
     <MinClientVersion>2.12</MinClientVersion>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <Authors>.NET Foundation and Contributors</Authors>
-    <PackageIconUrl>http://go.microsoft.com/fwlink/?LinkId=261274</PackageIconUrl>
+    <PackageIconUrl>https://raw.githubusercontent.com/dotnet/reactive/0f837d11385cfaf575861ccc5a5fbcafb22d888f/Rx.NET/Resources/Artwork/Logo.png</PackageIconUrl>
     <PackageProjectUrl>http://go.microsoft.com/fwlink/?LinkId=261273</PackageProjectUrl>
-    <PackageLicenseUrl>http://go.microsoft.com/fwlink/?LinkID=261272</PackageLicenseUrl>
+    <PackageLicenseExpression>Apache-2.0</PackageLicenseExpression>
     <PackageRequireLicenseAcceptance>true</PackageRequireLicenseAcceptance>    
     <DebugType>embedded</DebugType>
     <SignAssembly>true</SignAssembly>
@@ -25,12 +25,12 @@
   </PropertyGroup>
 
   <ItemGroup Condition="'$(IsTestProject)' != 'true' and '$(SourceLinkEnabled)' != 'false'">
-    <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.1" />
+    <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.2" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0-beta-62925-02" PrivateAssets="All"/>
   </ItemGroup>   
 
   <ItemGroup>
-    <PackageReference Include="Nerdbank.GitVersioning" Version="2.1.23" PrivateAssets="all" />
+    <PackageReference Include="Nerdbank.GitVersioning" Version="2.3.105" PrivateAssets="all" />
   </ItemGroup>
 
   <Target Name="AddCommitHashToAssemblyAttributes" BeforeTargets="GetAssemblyAttributes">