title: Update my pod causes error in GoogleDataTransport Umbrella header
body: <p>I've just updated my pod using "pod update" command and I use Firebase pod .
  I added new pod and when I compiled my project after that several errors appeared like this:</p>
  
  <pre><code>- Umbrella header for module 'GoogleDataTransport' does not include header 'GDTEventDataObject.h'
  - Umbrella header for module 'GoogleDataTransport' does not include header 'GDTClock.h'
  ...
  ...
  </code></pre>
  
  <p>I - use swift5 
    - Xcode 11.0 
    - macOS 10.15</p>