Bump doxia.version from 1.8 to 1.9
Bump doxia.version from 1.8 to 1.9

Bumps `doxia.version` from 1.8 to 1.9.

Updates `doxia-sink-api` from 1.8 to 1.9
- [Release notes](https://github.com/apache/maven-doxia/releases)
- [Commits](https://github.com/apache/maven-doxia/compare/doxia-1.8...doxia-1.9)

Updates `doxia-module-markdown` from 1.8 to 1.9
hazendaz/base-parent