avro

Bump exec-maven-plugin from 1.6.0 to 3.0.0 in /lang/java

Bumps [exec-maven-plugin](https://github.com/mojohaus/exec-maven-plugin) from 1.6.0 to 3.0.0.
- [Release notes](https://github.com/mojohaus/exec-maven-plugin/releases)
- [Commits](https://github.com/mojohaus/exec-maven-plugin/compare/exec-maven-plugin-1.6.0...exec-maven-plugin-3.0.0)

Signed-off-by: dependabot[bot] <support@github.com>