MAINTAINERS: Add Vladimir as co-maintainer for Block Jobs

MAINTAINERS: Add Vladimir as co-maintainer for Block Jobs

I'm developing Qemu backup for several years, and finally new backup
architecture, including block-copy generic engine and backup-top filter
landed upstream, great thanks to reviewers and especially to
Max Reitz!

I also have plans of moving other block-jobs onto block-copy, so that
we finally have one generic block copying path, fast and well-formed.

So, now I suggest to bring all parts of backup architecture into
"Block Jobs" subsystem (actually, aio_task is shared with qcow2 and
qemu-co-shared-resource can be reused somewhere else, but I'd keep an
eye on them in context of block-jobs) and add myself as co-maintainer.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210128144144.27617-1-vsementsov@virtuozzo.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>