fix: Removed Polyfill dependency for .NET 5

Author: samtrion

src/NetEvolve.Arguments/NetEvolve.Arguments.csproj

@@ -21,7 +21,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Polyfill" Condition=" '$(TargetFramework)' == 'netstandard2.0' or '$(TargetFramework)' == 'net5.0' ">
+    <PackageReference Include="Polyfill" Condition=" '$(TargetFramework)' == 'netstandard2.0' ">
       <PrivateAssets>all</PrivateAssets>
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>