Update agnhost image to match the one used in the tests

[mauriciopoppe]

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespaces from that line:

/kind api-change
/kind bug
/kind cleanup
/kind design
/kind documentation
/kind failing-test
/kind feature
/kind flake

What this PR does / why we need it:
Updates the agnhost image version to be the same one as the one used in the tests, the version was taken from https://github.com/kubernetes/kubernetes/blob/537941765fe1304dd096c1a2d4d4e70f10768218/test/utils/image/manifest.go#L234

Which issue(s) this PR fixes:

Related with the CI issue #892 in the Windows e2e tests

Does this PR introduce a user-facing change?:

NONE

[mauriciopoppe]

/cc @mattcary

[mattcary]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mattcary, mauriciopoppe

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