[core-workflow] "Awaiting merge" label for PRs from core devs

Hi. When core dev creates PR, "Awaiting merge" label is set automatically. It makes many "awaiting merge" PRs. It makes the label less useful, in my opinion. How about stop setting the label automatically? If the author wants review from other core-devs, they can set "awaiting core review" label manually. Other option is set "awaiting review" label instead of "awaiting merge", like PRs from other contributors. Regards, -- INADA Naoki <songofacandy@gmail.com>