github: add release-note description format to pull request template (#10235)
github: add release-note description format to pull request template (#10235)

Signed-off-by: Cadmus <CadmusJiang@gmail.com>

Co-authored-by: Ti Chi Robot <040e6455cde1c91e876ec337e785ce913eacba35@tidb.io>
BusyJay/tikv,BusyJay/tikv,BusyJay/tikv,BusyJay/tikv