Update actions/checkout action to v6.0.3 (#497)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/gradle-wrapper-validation.yml

@@ -6,5 +6,5 @@ jobs:
     name: "Validation"
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6.0.2
+      - uses: actions/checkout@v6.0.3
       - uses: gradle/actions/wrapper-validation@v6