Bump actions/upload-artifact from 4 to 6

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 4 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v4...v6)

---
updated-dependencies:
- dependency-name: actions/upload-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/scorecard.yml

@@ -59,7 +59,7 @@ jobs:
       # Upload the results as artifacts (optional). Commenting out will disable uploads of run results in SARIF
       # format to the repository Actions tab.
       - name: "Upload artifact"
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           name: SARIF file
           path: results.sarif

.github/workflows/stage-2-test.yaml

@@ -99,15 +99,15 @@ jobs:
         run: |
           echo "safe=$(echo '${{ matrix.workspace }}' | tr '/' '-_')" >> "$GITHUB_OUTPUT"
       - name: "Save the result of test suite"
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           name: unit-tests-${{ steps.names.outputs.safe }}
           path: "${{ matrix.workspace }}/.reports/unit"
           include-hidden-files: true
           if-no-files-found: ignore
         if: always()
       - name: "Save the result of code coverage"
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           name: code-coverage-${{ steps.names.outputs.safe }}
           path: "${{ matrix.workspace }}/.reports/unit/coverage/lcov.info"
@@ -195,7 +195,7 @@ jobs:
             --prepend-path-fix "../../"
 
       - name: Upload merged LCOV
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           name: code-coverage-report
           path: .reports/lcov.info