mercurial 3.1

Version bump from 3.0.2 to 3.1. I’ve also changed the mirror because
the current mirror doesn’t have the least 3.1 package up yet.
mercurial: update 3.1 bottle.

Closes #31299.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
cln: modernize

Finds gmp in non-local location under superenv.
cln: update 1.3.3 bottle.