Readme improvement (#5689)

Author: HongGit

eng/RuntimePackages.targets

@@ -46,6 +46,9 @@
     <Deterministic>true</Deterministic>
     <DebugType>portable</DebugType>
   </PropertyGroup>
+  <PropertyGroup Condition="Exists('README.md')">
+    <PackageReadmeFile>README.md</PackageReadmeFile>
+  </PropertyGroup>
   <ItemGroup>
     <None Include="$(PlaceholderFile)"
           Pack="true"

src/System.ServiceModel.Federation/src/System.ServiceModel.Federation.csproj

@@ -11,7 +11,6 @@
          proactively updated by the identity team and it now references vulnerable dependencies -->
     <CentralPackageTransitivePinningEnabled>true</CentralPackageTransitivePinningEnabled>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
-    <PackageReadmeFile>README.md</PackageReadmeFile>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\System.ServiceModel.Primitives\src\System.ServiceModel.Primitives.csproj" />

src/System.ServiceModel.Http/src/System.ServiceModel.Http.csproj

@@ -9,7 +9,6 @@
     <NoWarn>$(NoWarn);NU5131</NoWarn>
     <TargetFrameworks>$(DotNetVersion);$(NetFrameworkVersion);netstandard2.0</TargetFrameworks>
     <IsShipping>$(Ship_WcfPackages)</IsShipping>
-    <PackageReadmeFile>README.md</PackageReadmeFile>
   </PropertyGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' != '$(NetFrameworkVersion)'">

src/System.ServiceModel.NetFramingBase/src/System.ServiceModel.NetFramingBase.csproj

@@ -8,7 +8,6 @@
     <IsShipping>$(Ship_WcfPackages)</IsShipping>
     <TargetFrameworks>$(DotNetVersion)</TargetFrameworks>
     <RootNamespace>System.ServiceModel</RootNamespace>
-    <PackageReadmeFile>README.md</PackageReadmeFile>
   </PropertyGroup>
 
   <ItemGroup>

src/System.ServiceModel.NetNamedPipe/src/System.ServiceModel.NetNamedPipe.csproj

@@ -9,7 +9,6 @@
     <TargetFrameworks>$(DotNetVersion)</TargetFrameworks>
     <RootNamespace>System.ServiceModel</RootNamespace>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <PackageReadmeFile>README.md</PackageReadmeFile>
   </PropertyGroup>
 
   <ItemGroup>

src/System.ServiceModel.NetTcp/src/System.ServiceModel.NetTcp.csproj

@@ -9,7 +9,6 @@
     <NoWarn>$(NoWarn);NU5131</NoWarn>
     <TargetFrameworks>$(DotNetVersion);$(NetFrameworkVersion);netstandard2.0</TargetFrameworks>
     <IsShipping>$(Ship_WcfPackages)</IsShipping>
-    <PackageReadmeFile>README.md</PackageReadmeFile>
   </PropertyGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' != '$(NetFrameworkVersion)'">

src/System.ServiceModel.Primitives/src/System.ServiceModel.Primitives.csproj

@@ -17,7 +17,6 @@
          we wouldn't compile it anyway. -->
     <GenAPIGenerateReferenceAssemblySource>false</GenAPIGenerateReferenceAssemblySource>
     <IncludeSRCommonCode>false</IncludeSRCommonCode>
-    <PackageReadmeFile>README.md</PackageReadmeFile>
   </PropertyGroup>
   <ItemGroup Condition="'$(TargetFramework)' == '$(DotNetVersion)'">
     <InternalsVisibleTo Include="System.ServiceModel.Http" />

src/System.ServiceModel.UnixDomainSocket/src/System.ServiceModel.UnixDomainSocket.csproj

@@ -8,7 +8,6 @@
     <TargetFrameworks>$(DotNetVersion)</TargetFrameworks>
     <IsShipping>$(Ship_WcfPackages)</IsShipping>
     <PackageDescription>Provides the types that permit SOAP messages to be exchanged using Unix domain socket.</PackageDescription>
-    <PackageReadmeFile>README.md</PackageReadmeFile>
   </PropertyGroup>
 
   <ItemGroup>

src/System.Web.Services.Description/src/System.Web.Services.Description.csproj

@@ -10,7 +10,6 @@
     <TargetFrameworks>netstandard2.0;$(NetFrameworkVersion)</TargetFrameworks>
     <IsPartialFacadeAssembly Condition="'$(TargetFramework)' == '$(NetFrameworkVersion)'">true</IsPartialFacadeAssembly>
     <EnableDefaultItems Condition="'$(TargetFramework)' == '$(NetFrameworkVersion)'">false</EnableDefaultItems>
-    <PackageReadmeFile>README.md</PackageReadmeFile>
   </PropertyGroup>
 
   <ItemGroup Condition="'$(TargetFramework)' == '$(NetFrameworkVersion)'">