Roger's suggested changes to PR template

These are ideas Roger had for the template. I'll let him elaborate but I think the gist of it is that more people are checking against the Jira, and ensuring we're not blocked waiting for IPs to complete code review before merging.
The first checkbox in this list is `I agree with the assumptions made in the quality checklist`, the quality checklist being the top set of checkboxes the dev fills out, which includes `I've checked this work against the requirements of the Jira.`.

I guess we could include it twice though?