book: fix kustomize plugin doc
- [go/v3 plugin](./plugins/go-v3-plugin.md)
- [go/v2 plugin](./plugins/go-v2-plugin.md)
- [Declarative V1](./plugins/declarative-v1.md)
+ - [Kustomize V1](./plugins/kustomize-v1.md)
- [Plugins Versioning](./plugins/plugins-versioning.md)
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