WPForms Post Submissions Addon 1.6.0

### IMPORTANT
- Support for PHP 5.6 has been discontinued. If you are running PHP 5.6, you MUST upgrade PHP before installing WPForms Post Submissions 1.6.0. Failure to do that will disable WPForms Post Submissions functionality.
- Support for WordPress 5.4 and below has been discontinued. If you are running any outdated versions, you MUST upgrade WordPress before installing WPForms Post Submissions 1.6.0. Failure to do that will disable WPForms Post Submissions functionality.

### Changed
- The minimum WPForms version supported is 1.8.4.
- The help tooltip was removed in the Form Builder for consistency.

### Fixed
- Events were not created if the "Enable the Gutenberg block editor interface for creating events" option was enabled in the Events Calendar 6.3.5 plugin.

### Changed
- Minimum WPForms version supported is 1.8.3.

### Fixed
- Post featured Image field was prone to be set with incorrect settings.

### Added
- Compatibility with WPForms 1.6.8 and the updated Form Builder.
- Compatibility with the Rich Text field.

### Changed
- Improved compatibility with jQuery 3.5 and no jQuery Migrate plugin.
- Show settings in the Form Builder only if they are enabled.
- Show a modal in the Form Builder about available additional options only once.

### Fixed
- `0` values were not allowed to save as custom post meta.
- Images added as Post Featured Images didn't have titles.
- Events Calendar plugin compatibility: start/end times had incorrect timezone.