Use not "blkio" but "io" controller in cgroups v2

[orimanabu]

"blkio" controller seems to be available only for cgroups v1 according to man cgroups(7).

See also: #31

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[neolit123]

/approve
/cc @KentaTada @pacoxu

PTAL for LGTM
if we merge this it can be considered a bug fix, correct?

/kind bug

We can include it as a PATCH semver here, but backporting the vendor to k/k 1.24 doesn't seem necessary given users can skip the warning. Thoughts?

[pacoxu]

/lgtm
https://www.kernel.org/doc/Documentation/cgroup-v2.txt

The "io" controller regulates the distribution of IO resources. 

It's my fault. Thanks for the fix.

[neolit123]

looks like there is a gofmt error in CI.

[neolit123]

/ok-to-test

[pacoxu]

/lgtm

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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: neolit123, orimanabu, pacoxu

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[orimanabu]

Thank you for merging this PR!
This is my first contribution to Kubernetes.