Bump actions/checkout from 5 to 6 (#247)

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/cd.yml

@@ -25,7 +25,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     timeout-minutes: 20
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 1
       - name: Login to Docker Hub

.github/workflows/ci.yml

@@ -28,7 +28,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     timeout-minutes: 20
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 1
       - name: Set up JDK
@@ -60,7 +60,7 @@ jobs:
     runs-on: windows-latest
     timeout-minutes: 20
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 1
       - name: Login to Docker Hub

.github/workflows/release.yml

@@ -27,7 +27,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     timeout-minutes: 20
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 1
       - name: Login to Docker Hub

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

@@ -10,7 +10,7 @@ jobs:
   update-gradle-wrapper:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Update Gradle Wrapper
         uses: gradle-update/update-gradle-wrapper-action@v2
         with: