Bump vega-selections from 5.6.0 to 5.6.3 (#268)

Bumps [vega-selections](https://github.com/vega/vega) from 5.6.0 to 5.6.3.
- [Release notes](https://github.com/vega/vega/releases)
- [Commits](https://github.com/vega/vega/commits)

---
updated-dependencies:
- dependency-name: vega-selections
  dependency-version: 5.6.3
  dependency-type: indirect
...

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