Update Helm release postgres-cluster to v6

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| ghcr.io/gitroomhq/postiz-app | major | `v1.65.7` -> `v2.0.0` |

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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: #1020
Co-authored-by: Renovate Bot <renovate-bot@alexlebens.net>
Co-committed-by: Renovate Bot <renovate-bot@alexlebens.net>

clusters/cl01tl/applications/postiz/values.yaml

@@ -9,7 +9,7 @@ postiz:
         main:
           image:
             repository: ghcr.io/gitroomhq/postiz-app
-            tag: v1.65.7
+            tag: v2.0.0
             pullPolicy: IfNotPresent
           env:
             - name: MAIN_URL