update dag_run_id

import json

from astropy import time

import numpy as np

import string

import os

def gen_dag_run_id(digits=10):

def gen_dag_run_id(digits=6):

    """

    Generate a unique run_id for a dag.

    """

    now = time.Time.now()

    dag_run_id = now.iso[:10].replace("-", "")

    dag_run_id = now.strftime("%Y%m%d-%H%M%S-")

    n = len(string.ascii_lowercase)

    for i in range(digits):