Bump actions/checkout from 5 to 6 (#608)

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/release.yml

@@ -11,7 +11,7 @@ jobs:
     name: Publish
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 10000
       - run: git fetch --tags -f

.github/workflows/test.yml

@@ -22,7 +22,7 @@ jobs:
     name: Code format
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: scalafmt test
         run: ./sbt "+ scalafmtCheckAll"
   test_sbt1_plugin:
@@ -39,7 +39,7 @@ jobs:
             java: 24
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: actions/setup-java@v5
         with:
           distribution: "${{ matrix.distribution }}"
@@ -61,7 +61,7 @@ jobs:
   #           java: 24
   #   runs-on: ${{ matrix.os }}
   #   steps:
-  #     - uses: actions/checkout@v5
+  #     - uses: actions/checkout@v6
   #     - uses: actions/setup-java@v5
   #       with:
   #         distribution: "${{ matrix.distribution }}"