Messagepack (#12)

* add messagepack attributes

* fix isnullorempty

* bump api version

---------

Co-authored-by: rootdarkarchon <root.darkarchon@outlook.com>

MareSynchronosAPI/Dto/Group/GroupPairUserInfoDto.cs

@@ -1,6 +1,8 @@
 using MareSynchronos.API.Data;
 using MareSynchronos.API.Data.Enum;
+using MessagePack;
 
 namespace MareSynchronos.API.Dto.Group;
 
+[MessagePackObject(keyAsPropertyName: true)]
 public record GroupPairUserInfoDto(GroupData Group, UserData User, GroupUserInfo GroupUserInfo) : GroupPairDto(Group, User);