Consider Adding Full Support For Pushover Priority 2 Alerts

[peck]

Describe the feature request

Currently when setting a pushover alert to priority level 2 the following error message is displayed:

call to provider alert returned status code 400: {"expire":"must be supplied with priority=2","errors":["expire must be supplied with priority=2, see https://pushover.net/api#priority2"]}

Reviewing the pushover documentation, https://pushover.net/api#priority, it appears that when priority is set to 2 then two additional parameters are required:
retry - a numeric value representing the amount of time in seconds between retries
expire - a numeric value representing the total amount of time in seconds that a retry should be sent

Why do you personally want this feature to be implemented?

The ability to use priority 2 for pushover would allow for further use, and trust, of the critical notification feature on iOS that Pushover offers.

How long have you been using this project?

several months

Additional information

No response