Update Helm release grafana-operator to v5.20.0 (#1808)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [grafana-operator](https://github.com/grafana/helm-charts) | minor | `v5.19.4` -> `v5.20.0` |

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### Release Notes

<details>
<summary>grafana/helm-charts (grafana-operator)</summary>

### [`v5.20.0`](https://github.com/grafana/helm-charts/releases/tag/grafana-operator-v5.20.0)

[Compare Source](https://github.com/grafana/helm-charts/compare/grafana-operator-v5.19.4...grafana-operator-v5.20.0)

Helm chart for the [grafana-operator](https://github.com/grafana/grafana-operator)

Tag on source: <https://github.com/grafana/grafana-operator/releases/tag/v5.20.0>

</details>

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### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied.

♻ **Rebasing**: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update again.

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 - [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check this box

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Reviewed-on: #1808
Co-authored-by: Renovate Bot <renovate-bot@alexlebens.net>
Co-committed-by: Renovate Bot <renovate-bot@alexlebens.net>

clusters/cl01tl/monitoring/grafana-operator/Chart.yaml

@@ -17,7 +17,7 @@ maintainers:
   - name: alexlebens
 dependencies:
   - name: grafana-operator
-    version: v5.19.4
+    version: v5.20.0
     repository: https://grafana.github.io/helm-charts
   - name: postgres-cluster
     alias: postgres-17-cluster