postgres下插入只包含字符串的json会报错

```c#
using Newtonsoft.Json.Linq;

internal class Program
{
static void Main(string[] args)
{
IFreeSql fsql = new FreeSql.FreeSqlBuilder()
.UseConnectionString(FreeSql.DataType.PostgreSQL, @"Host=127.0.0.1;Port=5432;Username=postgres;Password=123; Database=freesqltest;")
.UseMonitorCommand(cmd => Console.WriteLine($"Sql：{cmd.CommandText}"))
.UseNoneCommandParameter(true)
.UseAutoSyncStructure(true)
.Build();

fsql.CodeFirst.SyncStructure();

fsql.Insert(new MyTestObj() { Json = "aaabbb" }).ExecuteAffrows();
}
}

class MyTestObj
{
public JToken Json { get; set; }
}
```
包：


freesql生成的sql：INSERT INTO "MyTestObj"("Json") VALUES('aaabbb')

可以正确插入的sql应该为 INSERT INTO "MyTestObj"("Json") VALUES('"aaabbb"')

update同理

不过数值类型没问题