title: Changing an Airflow's DAG end_date
body: <p>I have a set of DAGs that have run from <code>2011-01-01</code> to <code>2018-04-01</code> on a <code>@monthly</code> schedule. I've done this by setting the <code>start_date</code> and <code>end_date</code> on each of the dags. However, I've now realized I need it to run for one more month. I've updated the <code>end_date</code> to be <code>2018-05-01</code>, however updating this value has not triggered Airflow start another DagRun.</p>
  
  <p>I've read <a href="https://stackoverflow.com/questions/37294560/airflow-changing-the-crontab-time-for-a-dag-in-airflow?utm_medium=organic&amp;utm_source=google_rich_qa&amp;utm_campaign=google_rich_qa">Airflow: changing the crontab time for a DAG in Airflow</a>, but I do not want to change the Dag id because that would cause me to have to re-run all the months and I just want to add one additional month. Is this possible in Airflow? </p>