Update PULL_REQUEST_TEMPLATE.md (#54762)

* Update PULL_REQUEST_TEMPLATE.md

* Update PULL_REQUEST_TEMPLATE.md

Address review comments by moving changes into 'Checklist' section

* Update PULL_REQUEST_TEMPLATE.md

* Update .github/PULL_REQUEST_TEMPLATE.md

Co-authored-by: Franck Nijhof <frenck@frenck.nl>

* Update .github/PULL_REQUEST_TEMPLATE.md

Co-authored-by: Martin Hjelmare <marhje52@gmail.com>

Co-authored-by: Franck Nijhof <frenck@frenck.nl>
Co-authored-by: Martin Hjelmare <marhje52@gmail.com>