Bump superdesk-planning from 90a2176 to a26947d in /client (#147)

Bumps [superdesk-planning](https://github.com/superdesk/superdesk-planning) from `90a2176` to `a26947d`.
- [Release notes](https://github.com/superdesk/superdesk-planning/releases)
- [Commits](superdesk/superdesk-planning@90a2176...a26947d)

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

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