- Fixed bug in Google::Ads::GoogleAds::V18::Resources::CampaignBudget.

- Added support for Google Ads API v18.

- Updated example get_all_disapproved_ads to set returnTotalResultsCount
  on new searchSettings request field.

- Added support for Google Ads API v17_1.

- Removed support for Google Ads API v15.

- Added support for Google Ads API v17.

- Updated examples to remove usage of the page size parameter in Search
  requests.

- Added support for Google Ads API v16.1.

- Removed support for Google Ads API v14.
- Removed examples: approve_merchant_center_link, reject_merchant_center_link,
  remove_flights_feed_item_attribute_value, update_flights_feed_item_string_attribute_value,
  add_real_estate_feed, add_flights_feed.

- Added support for Google Ads API v16.0.

- Updated examples to remove references to extensions.
- Added support for a flag on the client that allows making requests
  without a developer token. This is in preparation for the pilot
  that uses Google Cloud orgs for API Access levels.
- Added local_services_lead.contact_details and
  local_services_lead_conversation.message_details.text to the fields
  to mask from logs.

- Removed support for Google Ads API v13.

- Added support for Google Ads API v15.0.

- Renamed upload_conversion_with_identifiers to
  upload_enhanced_conversions_for_leads and upload_conversion_enhancement to
  upload_enhanced_conversions_for_web, and updated these examples.
- Renamed get_product_bidding_category_constant to
  get_product_category_constants and updated.
- Updated examples: upload_offline_conversion, add_customer_match_user_list,
  upload_call_conversion, upload_store_sales_transactions,
  add_merchant_center_dynamic_remarketing_campaign, add_performance_max_product_listing_group_tree, add_performance_max_retail_campaign, add_shopping_product_ad.

- Added support for Google Ads API v14.1.

- Removed support for Google Ads API v12.
- Removed add_keyword_plan code example.
- Added code examples: generate_forecast_metrics, generate_historical_metrics.

- Added support for Google Ads API v14.

- Removed examples: generate_forecast_metrics, generate_historical_metrics,
  get_campaign_criterion_bid_modifier_simulations.