Update hashicorp/setup-terraform action to v4 (#82)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
|
[hashicorp/setup-terraform](https://redirect.github.com/hashicorp/setup-terraform)
| action | major | `v3` → `v4` |

---

### Release Notes

<details>
<summary>hashicorp/setup-terraform (hashicorp/setup-terraform)</summary>

###
[`v4`](https://redirect.github.com/hashicorp/setup-terraform/compare/v3...v4)

[Compare
Source](https://redirect.github.com/hashicorp/setup-terraform/compare/v3...v4)

</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 is behind base branch, 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 was generated by [Mend Renovate](https://mend.io/renovate/).
View the [repository job
log](https://developer.mend.io/github/riege/code-quality).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiI0My4yNi41IiwidXBkYXRlZEluVmVyIjoiNDMuMjYuNSIsInRhcmdldEJyYW5jaCI6Im1haW4iLCJsYWJlbHMiOlsiZGVwZW5kZW5jaWVzIl19-->

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/terraform.yml

@@ -27,7 +27,7 @@ jobs:
         uses: actions/checkout@v6
 
       - name: Setup terraform
-        uses: hashicorp/setup-terraform@v3
+        uses: hashicorp/setup-terraform@v4
 
       - name: Change working directory
         run: cd ${{ inputs.terraform_directory }}