Bump actions/checkout from 4.2.2 to 6.0.1

Bumps [actions/checkout](https://github.com/actions/checkout) from 4.2.2 to 6.0.1.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v4.2.2...v6.0.1)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: 6.0.1
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/gradle-ci-main.yml

@@ -36,7 +36,7 @@ jobs:
       packages: write
     steps:
       - name: Checkout
-        uses: actions/checkout@v4.2.2
+        uses: actions/checkout@v6.0.1
       - name: REUSE Compliance Check
         uses: fsfe/reuse-action@v5.0.0
       - name: Set up JDK 21

.github/workflows/gradle-ci.yml

@@ -14,7 +14,7 @@ jobs:
       contents: read
     steps:
       - name: Checkout
-        uses: actions/checkout@v4.2.2
+        uses: actions/checkout@v6.0.1
       - name: REUSE Compliance Check
         uses: fsfe/reuse-action@v5.0.0
       - name: Set up JDK 21

.github/workflows/gradle-release-app.yml

@@ -54,7 +54,7 @@ jobs:
           app-id: ${{ secrets.bot-app-id }}
           private-key: ${{ secrets.bot-private-key }}
       - name: Checkout
-        uses: actions/checkout@v4.2.2
+        uses: actions/checkout@v6.0.1
         with:
           ref: main
           token: ${{ steps.app-token.outputs.token }}

.github/workflows/gradle-release.yml

@@ -46,7 +46,7 @@ jobs:
       version: ${{ steps.Publish.outputs.version }}
     steps:
       - name: Checkout
-        uses: actions/checkout@v4.2.2
+        uses: actions/checkout@v6.0.1
         with:
           ref: main
           token: ${{ secrets.bot-token }}