Bump actions/checkout from 5 to 6 (#1883)

Co-authored-by: Boni Garcia <boni.garcia@uc3m.es>

Author: dependabot[bot]

.github/workflows/build.yml

@@ -18,7 +18,7 @@ jobs:
  runs-on: ${{ matrix.os }}
  steps:
  - name: Checkout GitHub repo
- uses: actions/checkout@v5
+ uses: actions/checkout@v6
  - name: Set up Java ${{ matrix.java }}
  uses: actions/setup-java@v5
  with: