chore(deps)!: update actions/checkout (v5.0.1 → v6.0.0) (#28)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://redirect.github.com/actions/checkout) |
action | major | `v5.0.1` -> `v6.0.0` |

---

### Release Notes

<details>
<summary>actions/checkout (actions/checkout)</summary>

###
[`v6.0.0`](https://redirect.github.com/actions/checkout/compare/v5.0.1...v6.0.0)

[Compare
Source](https://redirect.github.com/actions/checkout/compare/v5.0.1...v6.0.0)

</details>

---

### Configuration

📅 **Schedule**: Branch creation - At 12:00 AM through 04:59 AM and 10:00
PM through 11:59 PM, Monday through Friday ( * 0-4,22-23 * * 1-5 ), Only
on Sunday and Saturday ( * * * * 0,6 ) in timezone Europe/Helsinki,
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.

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

---

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

---

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.github/workflows/commitlint.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5.0.1
+      - uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
         with:
           fetch-depth: 0