Bump rector/rector from 2.1.7 to 2.2.1

Bumps [rector/rector](https://github.com/rectorphp/rector) from 2.1.7 to 2.2.1.
- [Release notes](https://github.com/rectorphp/rector/releases)
- [Commits](rectorphp/rector@2.1.7...2.2.1)

---
updated-dependencies:
- dependency-name: rector/rector
  dependency-version: 2.2.1
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]