title: Pandas: Add hour to timezone aware index
body: <p>I have to work with timezone aware timestamps and I am now struggling to do something as simple as adding an hour to my timezone index:</p>
  
  <p>Here is the setup:</p>
  
  <pre><code>import pandas as pd
  
  df = pd.DataFrame({"dato_tid" :['2020-03-29 01:00', '2020-03-29 03:00','2020-03-29 04:00']})
  df = df.set_index('dato_tid')
  df.index = pd.to_datetime(df.index)
  df = df.tz_localize('Europe/Oslo')
  </code></pre>
  
  <p>The datetimes are specifically chosen to hit the shift from daylight saving hours.  Now I want to add one hour to the entire index. Normally (in a timezone naive world) i would use:</p>
  
  <pre><code>df.index = df.index +pd.DateOffset(hours=1)
  </code></pre>
  
  <p>But this now crashes because it wants to move the '2020-03-29 01:00+01:00' to '2020-03-29 02:00+01:00' which does not exist.  </p>
  
  <p>Is there an easy way to add one hour to every element of my index?</p>