Bump codecov/codecov-action from 3 to 4 (#904)

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 3 to 4.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@v3...v4)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/codecov.yml

@@ -15,7 +15,7 @@ jobs:
         with:
           tool: cargo-tarpaulin
       - run: cargo tarpaulin --out Xml
-      - uses: codecov/codecov-action@v3
+      - uses: codecov/codecov-action@v4
         # A codecov token is not needed for public repos if the repo is linked
         # on codecov.io. See https://docs.codecov.com/docs/frequently-asked-questions#where-is-the-repository-upload-token-found
       - uses: actions/upload-artifact@v2