chore(deps): Update actions/checkout action to v5 (#375)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [actions/checkout](https://redirect.github.com/actions/checkout) | action | major | `v4` -> `v5` |

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### Release Notes

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

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

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

</details>

---

### Configuration

📅 **Schedule**: Branch creation - Between 12:00 AM and 03:59 AM, on day 1 of the month ( * 0-3 1 * * ) (UTC), 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

---

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

.github/workflows/lint_golang.yml

@@ -12,7 +12,7 @@ jobs:
     name: Lint with GolangCI
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
       - uses: actions/setup-go@v5
         with:
           go-version-file: go.mod

.github/workflows/lint_markdown.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Git checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: Vale
         uses: errata-ai/vale-action@v2
         with:
@@ -23,7 +23,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Git checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: markdownlint-cli
         uses: nosborn/[email protected]
         with:

.github/workflows/unittest.yml

@@ -20,7 +20,7 @@ jobs:
               git config --global core.autocrlf false
               git config --global core.eol lf
       - name: Check out code into the Go module directory
-        uses: actions/checkout@v4
+        uses: actions/checkout@v5
       - name: Set up Go 1.x
         uses: actions/setup-go@v5
         with: