Add documentation: Webhook : Integration examples: Uptime Kuma

[Slevin90]

To https://github.com/lovelaze/nebula-sync?tab=readme-ov-file#integration-examples
I would add Uptime Kuma, slightly different as the other examples as it used GET method.

WEBHOOK_SYNC_SUCCESS_URL=http://your-uptime-kuma:3001/api/push/{s={your-slug-or-guid-here}?status=up&msg=OK&ping=
WEBHOOK_SYNC_SUCCESS_METHOD=GET
WEBHOOK_SYNC_FAILURE_URL=http://your-uptime-kuma:3001/api/push/{your-slug-or-guid-here}?status=down&msg=fail&ping=
WEBHOOK_SYNC_FAILURE_METHOD=GET

[Slevin90]

Posted in Discussions as it's not a bug..