Retaget netstandard2.0 for Uno WebAssembly.

Author: jeromelaban

Xamarin.Essentials/Xamarin.Essentials.csproj

@@ -1,10 +1,10 @@
-<Project Sdk="MSBuild.Sdk.Extras/2.0.31">
+<Project Sdk="MSBuild.Sdk.Extras/2.0.54">
   <PropertyGroup>
     <TargetFrameworks Condition=" '$(OS)' == 'Windows_NT' ">netstandard1.0;netstandard2.0;Xamarin.iOS10;Xamarin.TVOS10;Xamarin.WatchOS10;MonoAndroid60;MonoAndroid70;MonoAndroid71;MonoAndroid80;MonoAndroid81;MonoAndroid90;uap10.0.16299;tizen40;</TargetFrameworks>
     <TargetFrameworks Condition=" '$(OS)' != 'Windows_NT' ">netstandard1.0;netstandard2.0;Xamarin.iOS10;Xamarin.TVOS10;Xamarin.WatchOS10;MonoAndroid60;MonoAndroid70;MonoAndroid71;MonoAndroid80;MonoAndroid81;MonoAndroid90;tizen40;</TargetFrameworks>
     <AssemblyName>Xamarin.Essentials</AssemblyName>
     <RootNamespace>Xamarin.Essentials</RootNamespace>
-    <PackageId>Xamarin.Essentials</PackageId>
+    <PackageId>Uno.Xamarin.Essentials</PackageId>
     <PackageIconUrl>https://raw.githubusercontent.com/xamarin/Essentials/master/Assets/xamarin.essentials_128x128.png</PackageIconUrl>
     <Summary>Xamarin.Essentials: a kit of essential API's for your apps</Summary>
     <PackageTags>xamarin, windows, ios, android, xamarin.forms, watchos, tvos, toolkit, Xamarin.Essentials, kit</PackageTags>
@@ -53,18 +53,31 @@
     <Compile Include="**\*.shared.cs" />
     <Compile Include="**\*.shared.*.cs" />
   </ItemGroup>
+  <!--
+  netstandard 2.0 is retargeted to support Wasm until .NET 5.0
   <ItemGroup Condition=" $(TargetFramework.StartsWith('netstandard1.')) ">
     <PackageReference Include="System.ValueTuple" Version="4.5.0" />
   </ItemGroup>
   <ItemGroup Condition=" $(TargetFramework.StartsWith('netstandard')) ">
     <Compile Include="**\*.netstandard.cs" />
     <Compile Include="**\*.netstandard.*.cs" />
   </ItemGroup>
+  -->
+  <ItemGroup Condition=" $(TargetFramework.StartsWith('netstandard2.0')) ">
+    <PackageReference Include="Uno.UI" Version="2.0.532" />
+    <Reference Include="System.Numerics" />
+    <Reference Include="System.Numerics.Vectors" />
+    <Compile Include="**\*.uwp.cs" />
+    <Compile Include="**\*.uwp.*.cs" />
+  </ItemGroup>
   <ItemGroup Condition=" $(TargetFramework.StartsWith('uap10.0')) ">
-    <PackageReference Include="Microsoft.NETCore.UniversalWindowsPlatform" Version="6.1.5" />
     <Compile Include="**\*.uwp.cs" />
     <Compile Include="**\*.uwp.*.cs" />
   </ItemGroup>
+  <PropertyGroup Condition=" $(TargetFramework.StartsWith('netstandard2.0')) ">
+    <NoWarn>$(NoWarn);Uno0001</NoWarn>
+    <NoWarn>$(NoWarn);NU1701</NoWarn> <!-- Remove this line once https://github.com/unoplatform/Uno.Core/issues/53 is fixed -->
+  </PropertyGroup>
   <ItemGroup Condition=" $(TargetFramework.StartsWith('MonoAndroid')) ">
     <Compile Include="**\*.android.cs" />
     <Compile Include="**\*.android.*.cs" />
@@ -96,7 +109,6 @@
     <Reference Include="System.Numerics.Vectors" />
   </ItemGroup>
   <ItemGroup Condition=" $(TargetFramework.StartsWith('tizen')) ">
-    <PackageReference Include="Tizen.NET" Version="4.0.0" />
     <Compile Include="**\*.tizen.cs" />
     <Compile Include="**\*.tizen.*.cs" />
   </ItemGroup>