[ENHANCEMENT] Consider moving from Newtonsoft to System.Text.Json

[nuttytree]

Description

In general it seems most major libraries are moving way from Newtonsoft to System.Text.Json. It would be good to see this library do the same.

Benefits

System.Text.Json seems to be the future of JSON parsing in .NET and is faster than Newtonsoft.

Detail

No response

Examples

No response

Risks/Downsides

No response

[nuttytree]

I did a little digging into this. For .NET 3.5/4.0 and .NET Standard 1.6 using System.Text.Json is not an option. However with a bit of conditional code it would be pretty easy and straightforward to switch .NET Standard 2.0 to System.Text.Json. Would you be open to me putting up a PR to make the change?