Bump actions/checkout from 3 to 4 (#16)

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>

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
         os: [ubuntu-latest, macos-latest, windows-latest]
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: notomo/action-setup-nvim-lua@v1
 
       - run: make new_rockspec VERSION=0.0.0

.github/workflows/release.yml

@@ -9,7 +9,7 @@ jobs:
     name: Release
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: notomo/action-setup-nvim-lua@v1
 
       - run: echo "version=${GITHUB_REF/refs\/tags\/v/}" >> $GITHUB_OUTPUT