add multiple frameworks (#127)

* add multiple frameworks

* fix

* fix client

Author: wanlwanl

samples/SimpleEcho/SimpleEcho.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.1</TargetFramework>
+    <TargetFrameworks>netcoreapp2.1;netcoreapp2.2;netcoreapp3.0;netcoreapp3.1</TargetFrameworks>
     <UserSecretsId>2da0d60d-9962-455e-97af-f0d2668c4ea1</UserSecretsId>
     <RootNamespace>Microsoft.Azure.SignalR.Samples.SimpleEcho</RootNamespace>
     <LangVersion>7.1</LangVersion>
@@ -11,10 +11,19 @@
     <Folder Include="wwwroot\" />
   </ItemGroup>
 
-  <ItemGroup>
+  <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp2.1' OR '$(TargetFramework)' == 'netcoreapp2.2'">
     <PackageReference Include="Microsoft.AspNetCore.App" />
-    <PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="1.0.0" />
-    <PackageReference Include="Microsoft.Azure.SignalR" Version="1.0.*" />
   </ItemGroup>
 
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Azure.SignalR" Version="1.4.*" />
+  </ItemGroup>
+
+    <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.0' OR '$(TargetFramework)' == 'netcoreapp3.1'">
+      <PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="3.1.*" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp2.1' OR '$(TargetFramework)' == 'netcoreapp2.2'">
+    <PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="1.0.0" />
+  </ItemGroup>
 </Project>