Re: [RFC PATCH 6/6] hex: allow only lowercase object IDs in breaking changes mode

"brian m. carlson" [off-list ref] writes:

Git has historically allowed either lowercase or uppercase hex for
object IDs, but it has always emitted only lowercase.  This has caused
people to expect only lowercase and not handle uppercase.

It is violation of Postel's Law by other people.  We do not
necessarily have to follow suit.

Even though I said throwing object names in a single category makes
sense, it may make sense to treat the object names that we locally
use to access our own object database and those that we use when
talking with _other_ people on the net separately for the Robustness
principle, we keep being strict in what we produce and stick to
lowercase, while accepting uppercase produced by those third-party
reimplementations of Git.