Update actions/setup-python action to v6 (#74)

This PR contains the following updates:

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

---

### Release Notes

<details>
<summary>actions/setup-python (actions/setup-python)</summary>

###
[`v6`](https://redirect.github.com/actions/setup-python/compare/v5...v6)

[Compare
Source](https://redirect.github.com/actions/setup-python/compare/v5...v6)

</details>

---

### 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.

🔕 **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/lint.yaml

@@ -19,7 +19,7 @@ jobs:
         with:
           version: 3.x
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install uv

.github/workflows/release.yaml

@@ -13,7 +13,7 @@ jobs:
         uses: actions/checkout@v5
 
       - name: Setup Python
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
 
       - name: Install uv
         uses: astral-sh/setup-uv@v7

.github/workflows/tests.yaml

@@ -19,7 +19,7 @@ jobs:
         with:
           version: 3.x
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install uv