Update ghcr.io/unpoller/unpoller Docker tag to v2.21.0 (#2943)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [ghcr.io/unpoller/unpoller](https://github.com/unpoller/unpoller) | minor | `v2.20.1` → `v2.21.0` |

---

### Release Notes

<details>
<summary>unpoller/unpoller (ghcr.io/unpoller/unpoller)</summary>

### [`v2.21.0`](https://github.com/unpoller/unpoller/releases/tag/v2.21.0)

[Compare Source](https://github.com/unpoller/unpoller/compare/v2.20.1...v2.21.0)

#### Changelog

- [`c71cc9a`](https://github.com/unpoller/unpoller/commit/c71cc9a68108217ee5634db5d99d540aedf49dc4) Merge pull request [#&#8203;905](https://github.com/unpoller/unpoller/issues/905) from aharper343/fix/nil-dereference
- [`25ba0bd`](https://github.com/unpoller/unpoller/commit/25ba0bd14ad6c258d0d36fdcae25e8d71a1f7d1c) Fix incorrect initialization of SaveTraffic
- [`db85517`](https://github.com/unpoller/unpoller/commit/db855171660fb24d7375cd794456e2a0ed32a694) Merge pull request [#&#8203;903](https://github.com/unpoller/unpoller/issues/903) from aharper343/feat/traffic-support
- [`f7d488a`](https://github.com/unpoller/unpoller/commit/f7d488a8877c9f6d18b19f54c9689d4b7cbd0da2) Lint and format cleanup
- [`9b62519`](https://github.com/unpoller/unpoller/commit/9b62519bfe5344f16ebc0d6e168fe4b21a403c05) Rebasing
- [`6205900`](https://github.com/unpoller/unpoller/commit/6205900446bda951bc1d79a52d3bc1ca25ff9bd7) Adding constants for periods and debug logs for retrieved counts
- [`ab7073d`](https://github.com/unpoller/unpoller/commit/ab7073d63d28bb8321c2f547cd43f215052a0b5f) Added support for regions and sub-regions
- [`22dfc25`](https://github.com/unpoller/unpoller/commit/22dfc258013afa80b202be107ffee62a9075e09d) Temp fix for test cases and warning from Dockerfile
- [`0b9d3de`](https://github.com/unpoller/unpoller/commit/0b9d3de5cca2659ff7f8cdfd12f3ee4714fc959b) First working version DPI metrics and traffic exported

</details>

---

### Configuration

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

---

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---

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Reviewed-on: https://gitea.alexlebens.dev/alexlebens/infrastructure/pulls/2943
Co-authored-by: Renovate Bot <renovate-bot@alexlebens.net>
Co-committed-by: Renovate Bot <renovate-bot@alexlebens.net>

clusters/cl01tl/helm/unpoller/values.yaml

@@ -9,7 +9,7 @@ unpoller:
         main:
           image:
             repository: ghcr.io/unpoller/unpoller
-            tag: v2.20.1
+            tag: v2.21.0
             pullPolicy: IfNotPresent
           env:
             - name: UP_UNIFI_CONTROLLER_0_SAVE_ALARMS