MAINTAINERS: add Akihiro Suda to maintainers

I'm nominating Akihiro to be added as a maintainer for runc. Akihiro has been a
frequent contributor to this project, bringing expertise in important areas, such
as cgroups v2 and rootless containers.

Akihiro has experience with collaborating on, and maintaining various mainstream
open source projects in the container ecosystem, and as such would be a great
addition to the list of maintainers to help this project moving forward.

With this pull request, I invite the maintainers to vote on this PR, as described
in the maintainers guide;
https://github.com/opencontainers/runc/blob/602c85fdc6c73d614213fc1759f8e710e54047ca/MAINTAINERS_GUIDE.md#how-are-maintainers-added

> The final vote to add a new maintainer should be approved by over 66% of the
> current maintainers with the chief maintainer having veto power. In case of a
> veto, conflict resolution rules expressed above apply. The voting period is
> five business days on the Pull Request to add the new maintainer.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

MAINTAINERS

@@ -3,3 +3,4 @@ Mrunal Patel <mpatel@redhat.com> (@mrunalp)
 Daniel, Dao Quang Minh <dqminh89@gmail.com> (@dqminh)
 Qiang Huang <h.huangqiang@huawei.com> (@hqhq)
 Aleksa Sarai <asarai@suse.de> (@cyphar)
+Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp> (@AkihiroSuda)