Bump codecov/codecov-action from v1.0.15 to v1.2.1 (#315)

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from v1.0.15 to v1.2.1.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/master/CHANGELOG.md)
- [Commits](codecov/codecov-action@v1.0.15...e156083)

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

Author: dependabot[bot]

.github/workflows/coverage.yml

@@ -28,7 +28,7 @@ jobs:
           coverage run --rcfile=.coveragerc -m pytest test/unit/test_dropbox_unit.py
           coverage xml
       - name: Publish Coverage
-        uses: codecov/codecov-action@v1.0.15
+        uses: codecov/codecov-action@v1.2.1
         with:
           flags: unit
           fail_ci_if_error: true