Support v3 pagerduty webhook JSON

What does this MR do and why?

Fixes issue in #383029 (closed)

Screenshots or screen recordings

Screen_Recording_2022-12-01_at_8.54.02_AM

How to set up and validate locally

1. Create PagerDuty account.
2. Follow steps mentioned in docs to setup the integration.
3. Create some test incidents and see them in the Issues list.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #383029 (closed)