Bump io.rest-assured:rest-assured in /modules/mockserver

Bumps [io.rest-assured:rest-assured](https://github.com/rest-assured/rest-assured) from 5.5.6 to 5.5.7.
- [Changelog](https://github.com/rest-assured/rest-assured/blob/master/changelog.txt)
- [Commits](https://github.com/rest-assured/rest-assured/compare/rest-assured-5.5.6...rest-assured-5.5.7)

---
updated-dependencies:
- dependency-name: io.rest-assured:rest-assured
  dependency-version: 5.5.7
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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