OPENNLP-1630 Move to Apache Parent 33 (#34)

- aligns version of Apache parent project to '33', details: https://github.com/apache/maven-apache-parent/releases/tag/apache-33
- drops outdated, custom-managed maven plugin versions (now via parent)
- updates maven.failsafe plugin to 3.5.1
- updates maven.assembly plugin to 3.6.0
1 file changed