chore(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)
- [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] <support@github.com>

Author: dependabot[bot]

.github/workflows/nextcloudfileproviderkit.yml

@@ -19,7 +19,7 @@ jobs:
         working-directory: shell_integration/MacOSX/NextcloudFileProviderKit
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: SwiftFormat
         run: swiftformat --lint . --reporter github-actions-log
@@ -32,7 +32,7 @@ jobs:
         working-directory: shell_integration/MacOSX/NextcloudFileProviderKit
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
 
     - uses: maxim-lobanov/setup-xcode@v1
       with: