C# - Add DateTime and Guid support

[fenglinnet]

I know before there were these new types of support. But after an update, these were lost. Please fix it. Thank you!
New types added to TinyJson #51

[linear]

SDK-828 C# - Add DateTime and Guid support

[novabyte]

@fenglinnet Would you be able to help with a pull request for this change? 🙏

[fenglinnet]

Thank you for your reply. Our project is currently integrating the Nakama, and we may need to make more adjustments in the future. Once everything is in place, we hope to submit some of these changes as a pull request to help improve the library.