deps: bump opencontainers/cgroups to v0.0.2, fix tests

[kolyshkin]

For opencontainers/cgroups changes, see
https://github.com/opencontainers/cgroups/releases/tag/v0.0.2

Fix integration tests according to changes in opencontainers/cgroups#4
(now the CPU quota value set is rounded the same way systemd does it).

Related to: #4639
Fixes: #4622

[rata]

This looks reasonable to me, but based on past experience, I think it would be great to run this in moby, containerd and kubernetes CI to make sure no one expects the old thing in tests.

I guess the Kubernetes CI can be the trickiest to run. I hope what is run on an open PR is enough to cover any regressions. But I can reach out to k8s people to ask, if you run into issues :)

[kolyshkin]

I think it would be great to run this in moby, containerd and kubernetes CI to make sure no one expects the old thing in tests.

Isn't it why we make pre-releases for?

Apparently k8s did something about it: kubernetes/kubernetes#131059.

I would also add cri-o and podman to the list of software whose tests are potentially broken by this update.

In any case, what's done is the right thing to do, because

• practically, the rounding doesn't matter;
• over time systemd may overwrite the value we wrote using fs driver;
• there is no way to work around the systemd overwriting.

So,

• if some tests will be broken, they need to be fixed in one way or another;
• I doubt any real applications will fail, it's mostly about the tests.