robo(ci): bump actions/upload-artifact from 2.2.4 to 2.3.1

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 2.2.4 to 2.3.1.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](https://github.com/actions/upload-artifact/compare/v2.2.4...v2.3.1)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/coverage.yml

@@ -32,7 +32,7 @@ jobs:
         uses: codecov/codecov-action@v2
 
       - name: Archive code coverage results
-        uses: actions/upload-artifact@v2.2.4
+        uses: actions/upload-artifact@v2.3.1
         with:
           name: code-coverage-report
           path: cobertura.xml