criu: Version 4.2.1

This release of CRIU (4.2.1) delivers a bunch of bugfixes we've
accumulated over the last year.

It should also simplify packaging work for downstreams, because it
also backports patches from
https://src.fedoraproject.org/rpms/criu/tree/rawhide and
https://salsa.debian.org/debian/criu/-/tree/master/debian/patches

Full changelog:
https://github.com/checkpoint-restore/criu/compare/v4.2...v4.2.1

We kindly request all distribution package maintainers to update CRIU
packages as soon as possible.

https://github.com/checkpoint-restore/criu/releases/tag/v4.2.1