message: [skip travis] Add another bit to the PR template
diff: @@ -20,6 +20,14 @@ _Remove the irrelevant one:_
  _Please state how this was tested:_
  +
  +
  +_Please tick which platforms this change was tested on:_
  +
  +- [ ] Windows
  +- [ ] macOS
  +- [ ] Linux
  +
  ## Checklist
  _Please ensure all are ticked (and actually done):_
  