chore(deps): update actions/setup-node action to v6 (#359)

This PR contains the following updates:

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

---

### Release Notes

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

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

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

</details>

---

### Configuration

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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/main.yml

@@ -19,7 +19,7 @@ jobs:
         uses: actions/checkout@v5
 
       - name: Setup Node.js
-        uses: actions/setup-node@v5
+        uses: actions/setup-node@v6
         with:
           node-version-file: '.nvmrc'
           cache: "npm"

.github/workflows/pr.yml

@@ -26,7 +26,7 @@ jobs:
           persist-credentials: false
 
       - name: Setup Node.js
-        uses: actions/setup-node@v5
+        uses: actions/setup-node@v6
         with:
           node-version-file: '.nvmrc'
           cache: npm
@@ -70,7 +70,7 @@ jobs:
           persist-credentials: false
 
       - name: Setup Node.js
-        uses: actions/setup-node@v5
+        uses: actions/setup-node@v6
         if: ${{ github.event.action != 'closed' }}
         with:
           node-version-file: '.nvmrc'