Bump actions/download-artifact from 2 to 4

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 2 to 4.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v2...v4)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/ci-python-sdk.yaml

@@ -621,7 +621,7 @@ jobs:
         run: |
           pip3 install coverage
       - name: Download all artifacts
-        uses: actions/download-artifact@v2
+        uses: actions/download-artifact@v4
         with:
           path: ./python-sdk/coverage
       - name: Run coverage
@@ -651,7 +651,7 @@ jobs:
           path: .test_durations
           key: test_durations-0-${{ github.run_id }}
       - name: Collect
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           path: ./python-sdk/artifacts
       - name: Consolidate and print durations