Bump actions/upload-artifact from 2.2.4 to 2.3.0 (#88)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 2.2.4 to 2.3.0.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v2.2.4...v2.3.0)

---
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>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/tests.yaml

@@ -49,7 +49,7 @@ jobs:
       - name: 🚀 Run pytest
         run: poetry run pytest --cov omnikinverter tests
       - name: ⬆️ Upload coverage artifact
-        uses: actions/upload-artifact@v2.2.4
+        uses: actions/upload-artifact@v2.3.0
         with:
           name: coverage-${{ matrix.python }}-${{ matrix.os }}
           path: .coverage