chore: add README.md to nuget package

Author: guitarrapc

Directory.Build.props

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <LangVersion>13</LangVersion>
+
+    <!-- NuGet Package Information -->
+    <PackageVersion>$(Version)</PackageVersion>
+    <Company>Cysharp</Company>
+    <Authors>Cysharp</Authors>
+    <Copyright>© Cysharp, Inc.</Copyright>
+    <PackageTags>task;async</PackageTags>
+    <PackageProjectUrl>https://github.com/Cysharp/UniTask</PackageProjectUrl>
+    <PackageReadmeFile>README.md</PackageReadmeFile>
+    <RepositoryUrl>$(PackageProjectUrl)</RepositoryUrl>
+    <RepositoryType>git</RepositoryType>
+    <PackageLicenseExpression>MIT</PackageLicenseExpression>
+    <PackageIcon>Icon.png</PackageIcon>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Include="$(MSBuildThisFileDirectory)README.md" Pack="true" PackagePath="\" />
+		<None Include="$(MSBuildThisFileDirectory)Icon.png" Pack="true" PackagePath="\" />
+  </ItemGroup>
+</Project>

src/UniTask.NetCore/Icon.png renamed to Icon.png

@@ -11,26 +11,12 @@
 
 		<!-- NuGet Packaging -->
 		<Id>UniTask</Id>
-		<PackageVersion>$(Version)</PackageVersion>
-		<Company>Cysharp</Company>
-		<Authors>Cysharp</Authors>
-		<Copyright>© Cysharp, Inc.</Copyright>
-		<PackageTags>task;async</PackageTags>
 		<Description>Provides an efficient async/await integration to Unity and .NET Core.</Description>
-		<PackageProjectUrl>https://github.com/Cysharp/UniTask</PackageProjectUrl>
-		<RepositoryUrl>$(PackageProjectUrl)</RepositoryUrl>
-		<RepositoryType>git</RepositoryType>
-		<PackageLicenseExpression>MIT</PackageLicenseExpression>
-		<PackageIcon>Icon.png</PackageIcon>
 		<SignAssembly>true</SignAssembly>
 		<AssemblyOriginatorKeyFile>opensource.snk</AssemblyOriginatorKeyFile>
 		<IsPackable>true</IsPackable>
 	</PropertyGroup>
 
-	<ItemGroup>
-		<None Include="Icon.png" Pack="true" PackagePath="/" />
-	</ItemGroup>
-
 	<ItemGroup>
 		<Compile Include="..\UniTask\Assets\Plugins\UniTask\Runtime\**\*.cs" Exclude="&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Editor\*.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\Triggers\*.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\Linq\UnityExtensions\*.cs;&#xD;&#xA;  &#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\Internal\UnityEqualityComparer.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\Internal\DiagnosticsExtensions.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\Internal\PlayerLoopRunner.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\Internal\ContinuationQueue.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\Internal\UnityWebRequestExtensions.cs;&#xD;&#xA;  &#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\UniTaskSynchronizationContext.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\CancellationTokenSourceExtensions.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\EnumeratorAsyncExtensions.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\TimeoutController.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\PlayerLoopHelper.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\PlayerLoopTimer.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\UniTask.Delay.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\UniTask.Run.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\UniTask.Bridge.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\UniTask.WaitUntil.cs;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\UnityAsyncExtensions.*;&#xD;&#xA;..\UniTask\Assets\Plugins\UniTask\Runtime\UnityBindingExtensions.cs;&#xD;&#xA;" />
 		<Compile Remove="..\UniTask\Assets\Plugins\UniTask\Runtime\_InternalVisibleTo.cs" />