Add netstandard2.0 to TargetFrameworks

Author: cnblogs-dudu

Enyim.Caching/Enyim.Caching.csproj

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <Description>EnyimMemcachedCore is a Memcached client library for .NET Core. Usage: Add services.AddEnyimMemcached(...) and app.UseEnyimMemcached() in Startup. Add IMemcachedClient into constructor.</Description>
     <Authors>cnblogs.com</Authors>
-    <TargetFrameworks>netstandard2.1;net5.0</TargetFrameworks>
+    <TargetFrameworks>netstandard2.0;netstandard2.1;net5.0</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <AssemblyName>EnyimMemcachedCore</AssemblyName>
     <PackageId>EnyimMemcachedCore</PackageId>