chore(deps): pin dependencies (#21)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://github.com/actions/checkout) | action | pinDigest |  -> `08c6903` |
| alpine | final | pinDigest |  -> `4b7ce07` |
| [docker/build-push-action](https://github.com/docker/build-push-action) | action | pinDigest |  -> `2634353` |
| [docker/login-action](https://github.com/docker/login-action) | action | pinDigest |  -> `5e57cd1` |
| [docker/setup-buildx-action](https://github.com/docker/setup-buildx-action) | action | pinDigest |  -> `e468171` |
| [dorny/paths-filter](https://github.com/dorny/paths-filter) | action | pinDigest |  -> `de90cc6` |

---

### 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 becomes conflicted, or you tick the rebase/retry checkbox.

👻 **Immortal**: This PR will be recreated if closed unmerged. Get [config help](https://github.com/renovatebot/renovate/discussions) if that's undesired.

---

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

---

This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).
<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0Mi4xLjMiLCJ1cGRhdGVkSW5WZXIiOiI0Mi4xLjMiLCJ0YXJnZXRCcmFuY2giOiJtYWluIiwibGFiZWxzIjpbImFjdGlvbiIsImRlcHMiXX0=-->

Reviewed-on: #21
Reviewed-by: t.behrendt <t.behrendt@noreply.localhost>
Co-authored-by: Renovate Bot <renovate@t00n.de>
Co-committed-by: Renovate Bot <renovate@t00n.de>

Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:3.22
+FROM alpine:3.22@sha256:4b7ce07002c69e8f3d704a9c5d6fd3053be500b7f1c69fc0d80990c2ad8dd412
 
 RUN apk update && apk add --no-cache \
     bash \