Bump actions/checkout from 5 to 6 in the all group

Bumps the all group with 1 update: [actions/checkout](https://github.com/actions/checkout).


Updates `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
  dependency-group: all
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/gradle.yaml

@@ -14,7 +14,7 @@ jobs:
   linux:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-java@v5
         with:
@@ -41,7 +41,7 @@ jobs:
   windows:
     runs-on: windows-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-java@v5
         with:
@@ -74,7 +74,7 @@ jobs:
       matrix:
         gradle: [ '8.13', '8.12.1', '8.11.1', '8.10.2', '8.9', '8.8', '8.7', '8.6', '8.5', '8.4', '8.3', '8.2.1', '8.1.1', '8.0.2', '7.6.4', '7.5.1', '7.4.2', '7.3.3', '7.2', '7.1.1', '7.0.2', '6.9.4', '6.8.3' ]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-java@v5
         with:
@@ -112,7 +112,7 @@ jobs:
       matrix:
         java: [ 8, 11, 17 ]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-java@v5
         with:
@@ -150,7 +150,7 @@ jobs:
       matrix:
         gradle: [ '9.2.0', '9.1.0', '9.0.0' ]
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-java@v5
         with:
@@ -178,7 +178,7 @@ jobs:
     needs: linux
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
 
       - uses: actions/setup-java@v5
         with: