chore(deps): update actions/setup-node action to v6 (#180)

This PR contains the following updates:

| Package | Type | Update | Change | OpenSSF |
|---|---|---|---|---|
| [actions/setup-node](https://redirect.github.com/actions/setup-node) |
action | major | `v4` -> `v6` | [![OpenSSF
Scorecard](https://api.securityscorecards.dev/projects/github.com/actions/setup-node/badge)](https://securityscorecards.dev/viewer/?uri=github.com/actions/setup-node)
|

---

### 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)

###
[`v5`](https://redirect.github.com/actions/setup-node/compare/v4...v5)

[Compare
Source](https://redirect.github.com/actions/setup-node/compare/v4...v5)

</details>

---

### Configuration

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are satisfied.

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---

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.github/workflows/solidity.yml

@@ -97,7 +97,7 @@ jobs:
       - name: Install Foundry
         uses: foundry-rs/foundry-toolchain@v1
 
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@v6
         with:
           node-version: 24.11.0