build(deps): bump codecov/codecov-action from 5 to 6 (#1435)

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 5 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@v5...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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/github-cxx-qt-tests.yml

@@ -113,7 +113,7 @@ jobs:
         # Note that --keep-only is important here to ensure crates.io paths don't conflict
         run: grcov . -s . --binary-path ./target/debug/ -t lcov --branch --ignore-not-existing --llvm --llvm-path /usr/lib/llvm-19/bin/ --keep-only "crates/*" -o ./target/debug/lcov.info --excl-start CODECOV_EXCLUDE_START --excl-stop CODECOV_EXCLUDE_STOP
       - name: upload-report
-        uses: codecov/codecov-action@v5
+        uses: codecov/codecov-action@v6
         with:
           directory: ./target/debug/
           disable-search: true