Bump org.apache.rat:apache-rat-plugin from 0.17 to 0.18

Bumps org.apache.rat:apache-rat-plugin from 0.17 to 0.18.

---
updated-dependencies:
- dependency-name: org.apache.rat:apache-rat-plugin
  dependency-version: '0.18'
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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