C# エラー「System.ArgumentException: shift_jis is not a supported encoding name」が発生した場合の対処法

Encoding.GetEncoding("shift_jis")

System.ArgumentException: 'shift_jis' is not a supported encoding name. For information on defining a custom encoding, s
ee the documentation for the Encoding.RegisterProvider method. (Parameter 'name')
   at System.Text.EncodingTable.InternalGetCodePageFromName(String name)
   at System.Text.EncodingTable.GetCodePageFromName(String name)
   at System.Text.Encoding.GetEncoding(String name)
   at testapp.Program.Main(String[] args) in C:\Users\testuser\Program.cs:line 23

Install-Package System.Text.Encoding.CodePages

System.Text.Encoding.RegisterProvider(System.Text.CodePagesEncodingProvider.Instance);