Upgrade Newtonsoft.Json to 13.0.1

[bdukes]

Summary

This PR upgrades DNN's dependency on Newtonsoft.Json from 10.x to 13.0.1.

This includes the following changes from their changelog:

• Types that implement ISerializable but don't have [SerializableAttribute] are not serialized using ISerializable
• Changed JsonProperty.MemberConverter to obsolete
• Changed camel casing logic for all caps words to not leave last character capitalized
• Changed enum serialization in dictionary keys to use EnumMemberAttribute
• JTokenReader now uses JsonReader.DateTimeZoneHandling setting for date values
• Excluded TargetSite when serializing Exceptions without SerializableAttribute
• Changed StringEnumConverter.ctor(bool camelCaseText) to obsolete
• Changed StringEnumConverter.CamelCaseText to obsolete
• JsonReader and JsonSerializer MaxDepth defaults to 64

[david-poindexter]

Looks great @bdukes - THANK YOU! 🎉

Looks like the build is delayed a bit in running - still in queue. So, barring no build issues, this looks good to me.