update go version to 1.21.5

[oliviassss]

What type of PR is this?

Uncomment only one, leave it on its own 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:
update go version to fix the failure in govlun check.
Which issue(s) this PR fixes:

Logs of a failed govlun check: https://github.com/kubernetes/cloud-provider-aws/actions/runs/7167984447/job/19515167548?pr=763
Special notes for your reviewer:

Does this PR introduce a user-facing change?:

NONE

[k8s-ci-robot]

This issue is currently awaiting triage.

If cloud-provider-aws contributors determine this is a relevant issue, they will accept it by applying the triage/accepted label and provide further guidance.

The triage/accepted label can be added by org members by writing /triage accepted in a comment.

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.

[cartermckinnon]

/lgtm
/approve

@oliviassss Can you open cherry-picks for this as well?

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: cartermckinnon

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [cartermckinnon]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[oliviassss]

@cartermckinnon, sure, which branch should I cherry pick to?

[cartermckinnon]

We should probably go all the way back to 1.23, I think every active branch is on go 1.21 now.

You can use the cherry pick script to open them quickly: https://kops.sigs.k8s.io/contributing/proposing-a-cherry-pick/