Update to use wp_after_insert_post hook to track event

[Rahmon]

Description of the Change

Since we're sending the categories in sectionNames field, we need to use the action wp_after_insert_post instead of transition_post_status. Otherwise, we'd get the old values (prior to the update)

Alternate Designs

Benefits

Possible Drawbacks

Verification Process

Checklist:

• I have read the CONTRIBUTING document.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests passed.

Applicable Issues

Changelog Entry

[felipeelia]

@Rahmon I'm not sure about how compatible we make the plugin with older WP versions but worth noting that wp_after_insert_post was only introduced in WP 5.6.0.

[jeffpaul]

@felipeelia the plugin is currently set with WP 5.6 as minimum version so seems like this would be ok then, yeah?

[felipeelia]

yup!