Simplify PR template

[antonymilne]

Description

This is an example of what the new template looks like!

I've removed the number of checkboxes that authors need to click:

• removed the "Types of changes" section which should be done by Label instead
• removed points that are no longer necessary from "Checklist" section
• put the two remaining points under "Notice" so you only need to check one box

Notice

• I acknowledge and agree that, by checking this box and clicking "Submit Pull Request":

  • I submit this contribution under the Apache 2.0 license and represent that I am entitled to do so on behalf of myself, my employer, or relevant third parties, as applicable.
  • I certify that (a) this contribution is my original creation and / or (b) to the extent it is not my original creation, I am authorized to submit this contribution on behalf of the original creator(s) or their licensees.
  • I certify that the use of this contribution as authorized by the Apache 2.0 license does not violate the intellectual property rights of anyone else.
  • I have not referenced individuals, products or companies in any commits, directly or indirectly.
  • I have not added data or restricted code in any commits, directly or indirectly.

[petar-qb]

Approved, but interested why we decided to remove "Types of changes" section?

[huong-li-nguyen]

Approved, but interested why we decided to remove "Types of changes" section?

The idea was to use the labels for the type of changes instead and simplify the template by having to check only one box :)