build(deps): bump actions/checkout from 3 to 4

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] <[email protected]>

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
         os: [ubuntu-latest]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Install Neovim
         shell: bash
         run: |
@@ -31,7 +31,7 @@ jobs:
     needs: tests
     if: ${{ github.ref == 'refs/heads/main' }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: panvimdoc
         uses: kdheepak/panvimdoc@main
         with:
@@ -61,7 +61,7 @@ jobs:
           package-name: lazy.nvim
           extra-files: |
             lua/lazy/core/config.lua
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: tag stable versions
         if: ${{ steps.release.outputs.release_created }}
         run: |