chore(deps): update helm release cloudnative-pg to v0.21.6 (#482)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [cloudnative-pg](https://cloudnative-pg.io) ([source](https://github.com/cloudnative-pg/charts)) | patch | `0.21.5` -> `0.21.6` |

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### Release Notes

<details>
<summary>cloudnative-pg/charts (cloudnative-pg)</summary>

### [`v0.21.6`](https://github.com/cloudnative-pg/charts/releases/tag/cloudnative-pg-v0.21.6)

[Compare Source](cloudnative-pg/charts@cloudnative-pg-v0.21.5...cloudnative-pg-v0.21.6)

CloudNativePG Operator Helm Chart

#### What's Changed

-   Add walStorage capability and remove gkeEnvironment conflict in cluster chart. by [@&#8203;rocket357](https://github.com/rocket357) in cloudnative-pg/charts#312
-   chore(deps): update actions/setup-python action to v5.1.1 by [@&#8203;renovate](https://github.com/renovate) in cloudnative-pg/charts#330
-   chore(deps): update docker/login-action action to v3.3.0 by [@&#8203;renovate](https://github.com/renovate) in cloudnative-pg/charts#333
-   chore: add support for `hostNetwork` in chart by [@&#8203;marckhair](https://github.com/marckhair) in cloudnative-pg/charts#324
-   feat(cloudnative-pg): Configuration of PodMonitor relabeling rules by [@&#8203;npdgm](https://github.com/npdgm) in cloudnative-pg/charts#148
-   fix: linter - trailing white spaces by [@&#8203;sxd](https://github.com/sxd) in cloudnative-pg/charts#339
-   Release cloudnative-pg-v0.21.6 by [@&#8203;github-actions](https://github.com/github-actions) in cloudnative-pg/charts#340

#### New Contributors

-   [@&#8203;rocket357](https://github.com/rocket357) made their first contribution in cloudnative-pg/charts#312
-   [@&#8203;marckhair](https://github.com/marckhair) made their first contribution in cloudnative-pg/charts#324
-   [@&#8203;npdgm](https://github.com/npdgm) made their first contribution in cloudnative-pg/charts#148

**Full Changelog**: cloudnative-pg/charts@cloudnative-pg-v0.21.5...cloudnative-pg-v0.21.6

</details>

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Reviewed-on: https://git.internal/nrdufour/home-ops/pulls/482
Co-authored-by: Renovate <[email protected]>
Co-committed-by: Renovate <[email protected]>

kubernetes/main/apps/database/cloudnative-pg/app/helm-release.yaml

@@ -10,7 +10,7 @@ spec:
   chart:
     spec:
       chart: cloudnative-pg
-      version: 0.21.5
+      version: 0.21.6
       sourceRef:
         kind: HelmRepository
         name: cloudnative-pg