message: Fix typo in druid granularity
diff: @@ -541,7 +541,7 @@ class DruidDatasource(Model, BaseDatasource):
  def time_column_grains(self):
  return {
  'time_columns': [
  - 'all', '5 seconds', '30 seconds', '1 minute', '5 minutes'
  + 'all', '5 seconds', '30 seconds', '1 minute', '5 minutes',
  '30 minutes', '1 hour', '6 hour', '1 day', '7 days',
  'week', 'week_starting_sunday', 'week_ending_saturday',
  'month', 'quarter', 'year',
  