Bump superdesk-planning from f5ad205 to a939213 in /client

Bumps [superdesk-planning](https://github.com/superdesk/superdesk-planning) from `f5ad205` to `a939213`.
- [Release notes](https://github.com/superdesk/superdesk-planning/releases)
- [Commits](superdesk/superdesk-planning@f5ad205...a939213)

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

Signed-off-by: dependabot[bot] <[email protected]>