4.0.0 - 2020-07-13
- Added support for Google Ads API v4_0.
- Renamed MutateJobService to BatchJobService.
- Added code examples: add_merchant_center_dynamic_remarketing_campaign,
  add_sitelinks_using_feeds, parallel_report_download, add_display_upload_ad, etc.

3.1.0 - 2020-05-07
- Added support for Google Ads API v3_1.
- Added code examples: upload_conversion_adjustment, upload_call_conversion,
  approve_merchant_center_link, search_for_language_and_carrier_constants,
  add_customer_match_user_list, etc.
- Improved code examples: add_complete_campaigns_using_mutate_job,
  get_account_hierarchy, get_account_budgets.

3.0.0 - 2020-02-26
- Added support for Google Ads API v3_0.
- Added SearchStreamHandler to support the search stream API.
- Added code examples: add_app_campaign, update_campaign_criterion_bid_modifier,
  add_listing_scope.
- Updated code examples get_campaigns and get_keyword_stats to use the search
  stream API.

2.2.0 - 2019-09-16
- Added support for Google Ads API v2_2.
- Added code examples: get_account_hierarchy, add_smart_display_ad, add_prices,
  add_sitelinks, forecast_reach, upload_offline_conversion, etc.

2.1.0 - 2019-08-15
- Added support for Google Ads API v2_1.
- Added examples for campaign experiments and mutate jobs.
- Added OperationService to support long running operations.

2.0.0 - 2019-06-28
- Added support for Google Ads API v2_0.

1.0.0 - 2019-06-24
- Initial release with support for Google Ads API v1_3.