Bump vega-interpreter from 2.0.0 to 2.2.1

Bumps [vega-interpreter](https://github.com/vega/vega) from 2.0.0 to 2.2.1.
- [Release notes](https://github.com/vega/vega/releases)
- [Commits](vega/vega@v2.0.0...v2.2.1)

---
updated-dependencies:
- dependency-name: vega-interpreter
  dependency-version: 2.2.1
  dependency-type: indirect
...

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Author: dependabot[bot]