Update actions/upload-artifact action to v6

Author: renovate[bot]

.github/workflows/e2e-tests.yaml

@@ -130,7 +130,7 @@ jobs:
 
       - name: Upload logs & client/server state
         if: failure()
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           name: e2e-${{ matrix.e2e-test }}-${{ runner.os }}-${{ matrix.python-version }}
           path: .e2e/${{ matrix.e2e-test }}