chore(deps): update actions/checkout action to v4 (#929)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://redirect.github.com/actions/checkout) |
action | major | `v3` -> `v4` |

---

### Release Notes

<details>
<summary>actions/checkout (actions/checkout)</summary>

###
[`v4`](https://redirect.github.com/actions/checkout/blob/HEAD/CHANGELOG.md#v422)

[Compare
Source](https://redirect.github.com/actions/checkout/compare/v3...v4)

- `url-helper.ts` now leverages well-known environment variables by
[@&#8203;jww3](https://redirect.github.com/jww3) in
[https://github.com/actions/checkout/pull/1941](https://redirect.github.com/actions/checkout/pull/1941)
- Expand unit test coverage for `isGhes` by
[@&#8203;jww3](https://redirect.github.com/jww3) in
[https://github.com/actions/checkout/pull/1946](https://redirect.github.com/actions/checkout/pull/1946)

</details>

---

### Configuration

📅 **Schedule**: Branch creation - "after 9pm,before 6am" in timezone
Europe/Zurich, Automerge - At any time (no schedule defined).

🚦 **Automerge**: Enabled.

♻ **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

---

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View the [repository job
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.github/workflows/dotnet-test.yml

@@ -14,7 +14,7 @@ jobs:
     name: Testing
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Setup .NET
         uses: actions/setup-dotnet@v3

.github/workflows/security-analysis.yml

@@ -23,7 +23,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v3