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] <support@github.com>

Author: dependabot[bot]

.github/workflows/checkstyle.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Setup asdf and install tools
       uses: asdf-vm/actions/install@v4
     - name: Setup Gradle

.github/workflows/coverage.yml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Setup asdf and install tools
       uses: asdf-vm/actions/install@v4
     - name: Setup Gradle

.github/workflows/cpd.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Setup asdf and install tools
         uses: asdf-vm/actions/install@v4
       - name: Setup Gradle

.github/workflows/gradle.yml

@@ -12,7 +12,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6
     - name: Setup asdf and install tools
       uses: asdf-vm/actions/install@v4
     - name: Setup Gradle

.github/workflows/mutation.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Setup asdf and install tools
         uses: asdf-vm/actions/install@v4
       - name: Setup Gradle

.github/workflows/pmd.yml

@@ -12,7 +12,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Setup asdf and install tools
         uses: asdf-vm/actions/install@v4
       - name: Setup Gradle

.github/workflows/release-please.yml

@@ -27,7 +27,7 @@ jobs:
       # Build and upload JAR artifact when a release is created
       - name: Checkout code
         if: ${{ steps.release.outputs.release_created }}
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Setup asdf and install tools
         if: ${{ steps.release.outputs.release_created }}

.github/workflows/spotbugs.yml

@@ -12,7 +12,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Setup asdf and install tools
         uses: asdf-vm/actions/install@v4
       - name: Setup Gradle