Is your feature request related to a problem? Please describe.
Using the same app/token, I would like to have a low priority push message sent when a backup task is completed successfully, and a high priority push message when something goes wrong.

As it is, I have no clue how backrest specifies a priority for the push message and the Gotify setup does not expose the priority field.

Describe the solution you'd like
Allow the user to set the push message priority by adding the priority field underneath the Title Template field.