Changes from PHP:
- If a user submits a POST request with an invalid reason,
they are returned back to the closure form with a BAD_REQUEST status.
- Now, users which created a PackageRequest have the ability to close
their own.
- Form action has been changed to `/requests/{id}/close`.
Closes https://gitlab.archlinux.org/archlinux/aurweb/-/issues/20
Signed-off-by: Kevin Morris <kevr@0cost.org>
