message: Correct kubernetes.ts file path in installation.md
  Correcting file path from `packages/backend/src/plugin/kubernetes.ts` to `packages/backend/src/plugins/kubernetes.ts`
diff: @@ -102,7 +102,7 @@ If either existing
  don't work for your use-case, it is possible to implement a custom
  [KubernetesClustersSupplier](https://backstage.io/docs/reference/plugin-kubernetes-backend.kubernetesclusterssupplier).
  -Change the following in `packages/backend/src/plugin/kubernetes.ts`:
  +Change the following in `packages/backend/src/plugins/kubernetes.ts`:
  ```diff
  -import { KubernetesBuilder } from '@backstage/plugin-kubernetes-backend';
  