Strip the patch number in GKE master version

[kahun]

What type of PR is this?
/kind bug

What this PR does / why we need it:
In GKE the patch number is stripped in the MachinePool object but not in GCPManagedControlPlane.

TODOs:

• squashed commits
• includes documentation
• adds unit tests

Release note:

Strip the patch number in GKE master version.

[k8s-ci-robot]

Hi @kahun. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[cpanato]

/ok-to-test

[cpanato]

/approve

/assign @richardcase

thanks!

[vincepri]

/lgtm

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cpanato, kahun, vincepri

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