A relational store has been configured without specifying either the DbConnection or connection stri

abp vnext使用Mysql报错：在项目中使用了最新的mysql 相关的引入出现这样的错误： “A relational store has been configured without specifying either the DbConnection or connection string to use.”

解决方案
**
在UseMysql上，要传递两个参数（connectionstring，ServerVersion）

只传递一个参数虽然执行迁移命令不会报错，但是执行Update-Database就会报错了。

贴以下完整的代码：

/* This class is needed for EF Core console commands
    * (like Add-Migration and Update-Database commands) */
public class WyJBLandDbContextFactory : IDesignTimeDbContextFactory<WyJBLandDbContext>
{
    public WyJBLandDbContext CreateDbContext(string[] args)
    {
        //BookStoreEfCoreEntityExtensionMappings.Configure();
        var configuration = BuildConfiguration();
        string conn = configuration.GetConnectionString("conn_mysql");
        AddTestLog(conn);
        var builder = new DbContextOptionsBuilder<WyJBLandDbContext>()
            .UseMySql(conn,ServerVersion.AutoDetect(conn));
        return new WyJBLandDbContext(builder.Options);
    }
    /// <summary>
    /// 记录一点内容用于测试
    /// </summary>
    /// <param name="content"></param>
    public void AddTestLog(string content) 
    {
        using (FileStream filestraem = new FileStream("d:/log.txt", FileMode.Append))
        {
            using (StreamWriter write = new StreamWriter(filestraem))
            {
                write.WriteLine(content);
                write.WriteLine("记录时间：" + DateTime.Now.ToString());
                write.WriteLine("----------------------------------------");
                write.Flush();
            }
        }
    }
    private static IConfigurationRoot BuildConfiguration()
    {
        var builder = new ConfigurationBuilder()
            .SetBasePath(Path.Combine(Directory.GetCurrentDirectory(), "../WY.JBLand.API/"))
            .AddJsonFile("appsettings.json", optional: true);
        return builder.Build();
    }
}