fix(deps): update module github.com/fluxcd/pkg/apis/kustomize to v1.18.0

[renovate]

This PR contains the following updates:

Package	Change	Age	Confidence
github.com/fluxcd/pkg/apis/kustomize	v1.15.0 → v1.18.0

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⚠️ Artifact update problem

Renovate failed to update an artifact related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

• any of the package files in this branch needs updating, or
• the branch becomes conflicted, or
• you click the rebase/retry checkbox if found above, or
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The artifact failure details are included below:

File name: go.sum

Command failed: go get -t ./...
go: downloading k8s.io/api v0.36.0
go: downloading k8s.io/apimachinery v0.36.0
go: downloading k8s.io/apiextensions-apiserver v0.36.0
go: downloading k8s.io/client-go v0.36.0
go: downloading k8s.io/apiserver v0.36.0
go: downloading github.com/fluxcd/pkg/apis/kustomize v1.18.0
go: downloading k8s.io/component-base v0.36.0
go: downloading k8s.io/streaming v0.36.0
go: github.com/projectcapsule/capsule/pkg/runtime/client imports
	github.com/fluxcd/pkg/ssa/jsondiff imports
	github.com/fluxcd/pkg/ssa/normalize imports
	k8s.io/api/autoscaling/v2beta2: cannot find module providing package k8s.io/api/autoscaling/v2beta2