Target netstandard2.0 in Vezel.Zig.Sdk-based projects to avoid NETSDK1215.

Author: alexrp

src/sdk/build/Vezel.Zig.Sdk.Overrides.targets

@@ -15,7 +15,7 @@
         <GenerateDependencyFile>false</GenerateDependencyFile>
         <IncludeBuildOutput>false</IncludeBuildOutput>
         <ShouldBeValidatedAsExecutableReference>false</ShouldBeValidatedAsExecutableReference>
-        <TargetFramework>netstandard1.0</TargetFramework>
+        <TargetFramework>netstandard2.0</TargetFramework>
     </PropertyGroup>
 
     <!--

src/sdk/build/Vezel.Zig.Sdk.Pack.targets

@@ -14,7 +14,7 @@
 
     <Target Name="_PackNativeAssets">
         <!--
-        Since we claim to support netstandard1.0 but do not package any managed
+        Since we claim to support netstandard2.0 but do not package any managed
         assemblies, NuGet will warn during package validation. We place a dummy
         file in the lib directory to silence it.
         -->