Add the syncronize action for pull request events
Revert "Add the syncronize action for pull request events"

This reverts commit b7c878a4261ab4e599d95f3971b06704000eeb2a.
Add the synchronizes event for pull request actions.
Add assignees to pull requests.
Add test for the pullrequest::assignee property.
Remove typo.
Remove unneeded JSON key path.
Add original_commit_id, clarify docs, add more tests.