Update capg 1.8.0

[barbacbd]

Vendor Cluster API Provider GCP version 1.8.0.

https://github.com/kubernetes-sigs/cluster-api-provider-gcp/tree/v1.8.0

[barbacbd]

/cc @r4f4 /cc @bfournie

[barbacbd]

/label platform/google

[openshift-ci[bot]]

@barbacbd: 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
ci/prow/e2e-aws-ovn-single-node	ae1f68bf0c2d420136cdee5503938eb51201eb82	link	false	/test e2e-aws-ovn-single-node

Full PR test history. Your PR dashboard.

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).

[openshift-merge-robot]

PR needs rebase.

Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository.

[sadasu]

/approve

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: sadasu

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/openshift/installer/blob/master/OWNERS)~~ [sadasu] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment