Support client-side Blazor with .NET Standard 2.1

Author: chucker

Blazor.PWA.MSBuild.Tasks/build/BlazorPWA.MSBuild.targets

@@ -9,6 +9,7 @@
     <BlazorProjectType Condition="'$(BlazorProjectType)' == '' AND '$(TargetFramework)' == 'netcoreapp3.1'">SSB</BlazorProjectType>
     <BlazorProjectType Condition="'$(BlazorProjectType)' == '' AND '$(TargetFramework)' == 'netcoreapp3.0'">SSB</BlazorProjectType>
     <BlazorProjectType Condition="'$(BlazorProjectType)' == '' AND '$(TargetFramework)' == 'netstandard2.0'">CSB</BlazorProjectType>
+    <BlazorProjectType Condition="'$(BlazorProjectType)' == '' AND '$(TargetFramework)' == 'netstandard2.1'">CSB</BlazorProjectType>
   </PropertyGroup>
 
   <PropertyGroup Label="ServiceWorker">
@@ -70,4 +71,4 @@
     <CallTarget Targets="BuildServiceWorker"/>
   </Target>
 
-</Project>
+</Project>