patchwork-bot: add ability to match by msgid

Patchwork API 1.2 allows us to match by msgid, so update patchwork-bot
to use Link: trailers for additional matching when we are unable to
match by patchwork hash.

Additionally, reworks caching that wasn't actually saving us any time
and drops the use of git patch-id that we used in the absence of msgid
matching.

Signed-off-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
1 file changed