Bump actions/checkout from 5 to 6 (#199)

Bumps [actions/checkout](https://github.com/actions/checkout) from 5 to 6.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v5...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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/build.yml

@@ -19,7 +19,7 @@ jobs:
   build:
     runs-on: macos-26
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - name: VERSION file changed
         id: version-file-changed

.github/workflows/gradle-wrapper-validation.yml

@@ -9,5 +9,5 @@ jobs:
    name: Gradle Wrapper Validation
    runs-on: ubuntu-latest
    steps:
-    - uses: actions/checkout@v5
+    - uses: actions/checkout@v6
     - uses: gradle/actions/wrapper-validation@v5