title: Firestore perform delete based on condition
body: <p>Is there a way I can perform a delete on <code>Firestore</code> documents where <strong>field1 =x</strong> and <strong>field2 = y?</strong></p>
  
  <p>I see the delete function but does not come with where.
  If I use the transaction then there is get and delete but the get does not seem to accept "where" clause.</p>
  
  <p>I hope I am missing something in the documentation.</p>
  
  <p>Thanks</p>