Bump piet-common from 0.6.2 to 0.7.0 (#726)

Bumps [piet-common](https://github.com/linebender/piet) from 0.6.2 to 0.7.0.
- [Release notes](https://github.com/linebender/piet/releases)
- [Commits](linebender/piet@v0.6.2...v0.7.0)

---
updated-dependencies:
- dependency-name: piet-common
  dependency-version: 0.7.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]