title: wildcard search in FileSensor airflow
body: <p>I have a file path as </p>
  
  <pre><code>fpath = "/path/abc20200216"
  </code></pre>
  
  <p>where date after abc keeps changing every month.</p>
  
  <p>Now I want to use this in FileSensor</p>
  
  <pre><code>file_sensor = FileSensor(task_id= "file_sensor_job", poke_interval= 30, filepath = fpath, run_as_user='xyzzy',dag=dag)
  </code></pre>
  
  <p>how can I pass a wildcard keyword in the Operator.</p>
  
  <p>Or is there any other alternative for sensing file in remote server using airflow?</p>