Update Helm release grafana to v6.20.8

This MR contains the following updates:

Package	Update	Change
grafana (source)	patch	6.20.7 -> 6.20.8

---

Release Notes

grafana/helm-charts

v6.20.8

Compare Source

The leading tool for querying and visualizing time series and metrics.

---

Configuration

📅 Schedule: At any time (no schedule defined).

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

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

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

---

• If you want to rebase/retry this MR, click this checkbox.

---

This MR has been generated by Renovate Bot.