Bump appassembler-maven-plugin from 1.9 to 2.1.0
Bump appassembler-maven-plugin from 1.9 to 2.1.0

Bumps [appassembler-maven-plugin](https://github.com/mojohaus/appassembler) from 1.9 to 2.1.0.
- [Release notes](https://github.com/mojohaus/appassembler/releases)
- [Commits](https://github.com/mojohaus/appassembler/compare/appassembler-1.9...appassembler-2.1.0)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
adamretter/csv-validator,digital-preservation/csv-validator