chore: bump actions/checkout from 3 to 4 (docsifyjs#2248)

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/test.yml

@@ -9,7 +9,7 @@ jobs:
       matrix:
         node-version: ['lts/*']
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Setup Node.js ${{ matrix.node-version }}
         uses: actions/setup-node@v3
         with:
@@ -30,7 +30,7 @@ jobs:
         node-version: ['lts/*']
         os: ['macos-latest', 'ubuntu-latest', 'windows-latest']
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Setup Node.js ${{ matrix.node-version }}
         uses: actions/setup-node@v3
         with:
@@ -51,7 +51,7 @@ jobs:
       matrix:
         node-version: ['lts/*']
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Setup Node.js ${{ matrix.node-version }}
         uses: actions/setup-node@v3
         with: