Enable auto-merge on PR

**Is your feature request related to a problem? Please describe.**
N/A

**Describe the solution you'd like**
Add an option so that when checks pass and approval is given on a PR, it will [auto-merge](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/incorporating-changes-from-a-pull-request/automatically-merging-a-pull-request)

**Describe alternatives you've considered**
An action to merge when approved, though this would eat up some actions minutes, and there is a built-in github feature for this behabiour.

**Additional context**
N/A