criu: 3.8 -> 3.8.1

Semi-automatic update generated by https://github.com/ryantm/nixpkgs-update tools.

This update was made based on information from https://repology.org/metapackage/criu/versions.

These checks were done:

- built on NixOS
- ran `/nix/store/yqfshz1c0qp2h8vdcswiaknxb6ibxfsl-criu-3.8.1/bin/compel -h` got 0 exit code
- ran `/nix/store/yqfshz1c0qp2h8vdcswiaknxb6ibxfsl-criu-3.8.1/bin/compel --help` got 0 exit code
- ran `/nix/store/yqfshz1c0qp2h8vdcswiaknxb6ibxfsl-criu-3.8.1/bin/criu -h` got 0 exit code
- ran `/nix/store/yqfshz1c0qp2h8vdcswiaknxb6ibxfsl-criu-3.8.1/bin/criu --help` got 0 exit code
- ran `/nix/store/yqfshz1c0qp2h8vdcswiaknxb6ibxfsl-criu-3.8.1/bin/criu -V` and found version 3.8.1
- ran `/nix/store/yqfshz1c0qp2h8vdcswiaknxb6ibxfsl-criu-3.8.1/bin/criu --version` and found version 3.8.1
- found 3.8.1 with grep in /nix/store/yqfshz1c0qp2h8vdcswiaknxb6ibxfsl-criu-3.8.1
- directory tree listing: https://gist.github.com/4324a1815464a7da41c4b8cd5056b1b7