Bump codecov/codecov-action from 4 to 6 (#74)

* Bump codecov/codecov-action from 4 to 6

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 4 to 6.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@v4...v6)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

* Apply suggestion from @odow

---------

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

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -48,7 +48,7 @@ jobs:
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
       - uses: julia-actions/julia-processcoverage@v1
-      - uses: codecov/codecov-action@v4
+      - uses: codecov/codecov-action@v6
         with:
-          file: lcov.info
+          files: lcov.info
           token: ${{ secrets.CODECOV_TOKEN }}