Bump superdesk-planning from 6539a16 to 6f0c25b in /client (#551)

Bumps [superdesk-planning](https://github.com/superdesk/superdesk-planning) from `6539a16` to `6f0c25b`.
- [Release notes](https://github.com/superdesk/superdesk-planning/releases)
- [Commits](superdesk/superdesk-planning@6539a16...6f0c25b)

---
updated-dependencies:
- dependency-name: superdesk-planning
  dependency-type: direct:production
...

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