Update PR template

[celinval]

Change Description

Change the template to be more concise to address the team's concern that the template was too verbose.

Call-outs

1. I don't think we need the disclaimer at the bottom, but I'm keeping it for now.
2. BTW, I do like the call-outs to provide context to the PR, but I believe we can leave it to the author's discretion.

Note: By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses.

[zhassan-aws]

IMHO, the current template is clearer, and is more convenient to fill out because of the structure it provides. It could use some cleanup though (e.g. removing the checkboxes list, and perhaps the testing section). Would that make the commit message too cumbersome?

[adpaco-aws]

Would that make the commit message too cumbersome?

In my opinion, they'll be a bit harder to read. But that's not the only problem: including structure will make them more difficult to distinguish because they'll include repeated content (for example, think about how git log would look like).

Should we update our development documentation to clearly state that we'll be using the PR description as the commit message? And what parts to remove before doing so, too.

[JustusAdam]

Seems reasonable

[celinval]

I don't think there's a perfect solution here, but this is also a small problem that I don't think it's worth spending too much time. The goal is to reduce unnecessary burden and ensure that our git history captures the right amount of information.

Thank you for all the feedback! I'm going ahead with the current proposal, and I think we can adjust later.