Bump johnzon.version from 1.2.15 to 1.2.18

Bump johnzon.version from 1.2.15 to 1.2.18

Bumps `johnzon.version` from 1.2.15 to 1.2.18.

Updates `johnzon-core` from 1.2.15 to 1.2.18

Updates `johnzon-mapper` from 1.2.15 to 1.2.18

---
updated-dependencies:
- dependency-name: org.apache.johnzon:johnzon-core
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: org.apache.johnzon:johnzon-mapper
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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