Update quay.io/cilium/certgen Docker tag to v0.2.1

[gardener-ci-robot]

This PR contains the following updates:

Package	Update	Change
quay.io/cilium/certgen	patch	v0.2.0 -> v0.2.1

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Configuration

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This PR has been generated by Renovate Bot.

[gardener-robot]

@gardener-ci-robot Thank you for your contribution.

[gardener-prow]

@gardener-ci-robot: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-extension-networking-cilium-e2e-kind	3c394f7	link	true	/test pull-extension-networking-cilium-e2e-kind

Full PR test history. Your PR dashboard. Command help for this repository.
Please help us cut down on flakes by linking this test failure to an open flake report or filing a new flake report if you can't find an existing one. Also see our testing guideline for how to avoid and hunt flakes.

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