Elementor Pro 3.21.1

* New! - Added Drip integration to Forms
* New! - Added ActiveCampaign integration to Forms
* New! - Added ConverKit integration to Forms
* New! - Added GetResponse integration to Forms
* New! - Added form `id`, `name` attributes to handle integration with auto collectors like HubSpot
* New! - Added Global API key for MailChimp to improve the workflow
* Tweak! - Better error handling and message display for Forms
* Fix! - PHP notice Undefined variable `$cc_header`

* New! - Added a native Comments widget ([#543](Post Elements - Page Title, Content, Etc · Issue #543 · pojome/elementor · GitHub))
* New! - Added an Author Box widget
* New! - Added a Post Navigation widget
* New! - Added a Yoast Breadcrumbs widget ([#2749]([Feature request] Breadbrumbs · Issue #2749 · pojome/elementor · GitHub))
* Tweak! - Added a close button to search widget under Full Screen skin (#2762)([#2878](Missing save widget icon · Issue #2878 · pojome/elementor · GitHub))
* Fix! - Allow currency symbol to appear even if price isn't numeric
* Fix! - Edge cases when the nav menu is empty in a stretched section
* Fix! - Added fallback when you remove the `space-between` on Swiper carousel

* Fix! - Missing save widget icon
* Fix! - Global widgets not saving edits
* Fix! - Removed `white-space: nowrap;` property from vertical menu in Nav Menu widget