Resolve 'IBM437' is not a supported encoding name EPPlus

First add a reference to System.Text.Encoding.CodePages assembly.

<ItemGroup>
    <PackageReference Include="System.Text.Encoding.CodePages" Version="4.3.0" />
</ItemGroup>

Then register the missing parts:

 Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);

Reference

• https://github.com/JanKallman/EPPlus/issues/31