Bump actions/download-artifact from 5 to 6

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v5...v6)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  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/stage-2-test.yaml

@@ -152,11 +152,11 @@ jobs:
         with:
           fetch-depth: 0 # Full history is needed to improving relevancy of reporting
       - name: "Download coverage report for SONAR"
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: code-coverage-report
       - name: "Download Python coverage reports"
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: python-coverage-reports
           path: src/

.github/workflows/stage-5-publish.yaml

@@ -46,13 +46,13 @@ jobs:
         uses: actions/checkout@v5
 
       - name: "Get artifacts: jekyll docs"
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           path: ./artifacts/jekyll-docs-${{ inputs.version }}
           name: jekyll-docs-${{ inputs.version }}
 
       - name: "Get artifacts: schema"
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           path: ./artifacts/schemas-${{ inputs.version }}
           name: schemas-${{ inputs.version }}