chore(deps): update actions/setup-go action to v6 (#64)

This PR contains the following updates:

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

---

### Release Notes

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

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

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

</details>

---

### Configuration

📅 **Schedule**: Branch creation - "before 9am on Monday" (UTC),
Automerge - At any time (no schedule defined).

🚦 **Automerge**: Enabled.

♻ **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

---

This PR has been generated by [Renovate
Bot](https://redirect.github.com/renovatebot/renovate).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIwLjAuMC1zZW1hbnRpYy1yZWxlYXNlIiwidXBkYXRlZEluVmVyIjoiMC4wLjAtc2VtYW50aWMtcmVsZWFzZSIsInRhcmdldEJyYW5jaCI6Im1haW4iLCJsYWJlbHMiOlsiZGVwZW5kZW5jaWVzIl19-->

Co-authored-by: ivy-s-renovate-bot[bot] <263067818+ivy-s-renovate-bot[bot]@users.noreply.github.com>

Author: ivy-s-renovate-bot[bot]

.github/workflows/ci.yml

@@ -14,7 +14,7 @@ jobs:
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
 
       - name: Set up Go
-        uses: actions/setup-go@40f1582b2485089dde7abd97c1529aa768e1baff # v5
+        uses: actions/setup-go@7a3fe6cf4cb3a834922a1244abfce67bcef6a0c5 # v6
         with:
           go-version: '1.25.7'