LPS-44671 Edits to breaking changes skeleton

/cc @brianchandotcom @rotty3000 @juliocamarero @natecavanaugh @eduardolundgren

I'm sending this to Jorge as he is going to writeup some initial breaking changes as examples for folks to follow.

Here are some notable changes:
* Added Jira ticket field
* Described the Date field as the date you submitted the change. That way, when a developer submits his pull, he can use that date (or an approximate date). I left the format to include the day of the month. If we only required the year and month (e.g., YYYY-MM), developers might wonder where to put their change in the list.

Original PR: https://github.com/brianchandotcom/liferay-portal/pull/16974

Thanks