`DateTime` loses precision when bound as a parameter

DateTime ticks are truncated when they are used as a parameter. (e.g., '2020-01-01 00:00:00.1333333' is bound as '2020-01-01 00:00:00.1330000')

Here is a repro illustrating the issue. (note that a vanilla SqlCommand works!)

Please let me know if this is an issue on my end, or if it's with the repo, where the fix might be. I'm happy to open a PR.

using Dapper;
using Microsoft.Data.SqlClient;
using System;

namespace DapperDateTimeRepro
{
    class Program
    {
        static void Main(string[] args)
        {
            var connectionString = new SqlConnectionStringBuilder
            {
                DataSource = "(localdb)\\MSSQLLocalDB",
                IntegratedSecurity = true,
                Pooling = true
            }.ConnectionString;

            var dateTimeWithTicks = new DateTime(2020, 1, 1, 0, 0, 0, DateTimeKind.Utc);
            dateTimeWithTicks = dateTimeWithTicks.AddTicks(1333333);

            using (var conn = new SqlConnection(connectionString))
            {
               // 2020-01-01 00:00:00:.1330000
                var roundTrip = conn.QuerySingle<DateTime>("SELECT @x", new { x = dateTimeWithTicks }); 
                var roundTripEquals = roundTrip == dateTimeWithTicks; // false!

                var readOnly = conn.QuerySingle<DateTime>(@"
                    DECLARE @existing datetime2 = '2020-01-01 00:00:00.1333333'
                    SELECT @existing");
                var readOnlyEquals = readOnly == dateTimeWithTicks; // true!

                // now use SQLCommand instead of Dapper
                conn.Open();
                var command = conn.CreateCommand();
                command.CommandText = "SELECT @x";
                
                var param = command.CreateParameter();
                param.DbType = System.Data.DbType.DateTime2;
                param.Value = dateTimeWithTicks;
                param.ParameterName = "x";
                command.Parameters.Add(param);
                
                var reader = command.ExecuteReader();
                reader.Read();

                var noDapper = (DateTime)reader.GetValue(0);
                noDapper = DateTime.SpecifyKind(noDapper, DateTimeKind.Utc);
                reader.Close();

                var noDapperEquals = noDapper == dateTimeWithTicks; // true!
            }
        }
    }
}

Start with the supplied C# repro, comparing Dapper's parameter binding with the Microsoft.Data.SqlClient SqlCommand path. Trace how the DateTime parameter is created and verify the fix by confirming that the round-trip value retains the original ticks, matching the direct SqlCommand result.