title: Pandas read_gbq() does not load columns containing dots
body: <p>I am using read_gbq() to load a Big Query table into a Jupyter notebook with the following code:</p>
  <pre><code># Define SQL query
  sql = &quot;&quot;&quot;
      SELECT *
      FROM `xxx.xxx.xxx`
      WHERE timestamp &gt; TIMESTAMP('2021-03-11 00:00:00') AND timestamp &lt; TIMESTAMP('2021-03-12 00:00:00')
      ORDER BY timestamp 
  &quot;&quot;&quot;
  # Run a Standard SQL query using the environment's default project
  df = pd.read_gbq(sql, dialect='standard')
  </code></pre>
  <p>The table gets stored into df but columns with names containing a dot, e.g. <code>labels.type</code> do not get loaded (they are simply missing, no error is thrown). <br>
  When I do the same query in BigQuery itself, I see the correct table in the Preview window (i.e. <code>labels.type</code> is not missing).</p>
  <p>What might be the reason to this?</p>