build(deps): Bump actions/checkout from 4 to 6

Bumps [actions/checkout](https://github.com/actions/checkout) from 4 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4...v6)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
         swift: ['6.1']
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
     - name: Setup Swift
       uses: swift-actions/setup-swift@v2

.github/workflows/release.yml

@@ -15,7 +15,7 @@ jobs:
     name: Test
     runs-on: macos-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
     - name: Setup Swift
       uses: swift-actions/setup-swift@v2
@@ -35,7 +35,7 @@ jobs:
     if: github.ref == 'refs/heads/main'
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
       with:
         fetch-depth: 0
 

.github/workflows/swiftlint.yml

@@ -10,7 +10,7 @@ jobs:
   swiftlint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: GitHub Action for SwiftLint
         uses: norio-nomura/[email protected]