Update versions of *-artifact actions

Author: data-douser

.github/workflows/codeql-qlt-unit-tests.yml

@@ -147,7 +147,7 @@ jobs:
       - name: Upload test results
         # Upload results even if tests failed, but only if the language is valid
         if: ${{ always() && matrix.language && matrix.language != 'unknown' }}
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v5
         with:
           name: qlt-test-results-${{ matrix.language }}-${{ runner.os }}
           path: |
@@ -171,7 +171,7 @@ jobs:
           install-ql-packs: false
 
       - name: Download CodeQL unit test results
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           pattern: qlt-test-results-*
           path: test-results/