Breaking changes:
* Various enums such as “DeliveryReceiptType,” “ResultsDisclosureType,” and “VotingMode” replaced the previous integer-based type mappings
Added support for group message types
Added many new message types
Deserialization of additional message types is now supported
Added quote helper functions to the “GroupTextMessage” and “TextMessage” message types to facilitate determining message quotes
Added configurable User-Agent header
Started targeting .NET Framework 4.8
Numerous security and stability improvements
Miscellaneous bug fixes
Updated dependencies
