fixed Maven warnings, updated plugin versions

[michelou]

This PR fixes Maven warnings (e.g. missing groupId) and updates several plugin versions.

We will also submit a separate PR which adds support for batch files in component/pom.xml and native/pom.xml (i.e <executable>${basedir}/make_component.sh</executable>) when executing mvn clean package on Microsoft Windows (see my fork).

[graalvmbot]

Hello Stéphane Micheloud, thanks for contributing a PR to our project!

We use the Oracle Contributor Agreement to make the copyright of contributions clear. We don't have a record of you having signed this yet, based on your email address stephane -(dot)- micheloud -(at)- crealp -(dot)- vs -(dot)- ch. You can sign it at that link.

If you think you've already signed it, please comment below and we'll check.

[michelou]

I sent the OCA to oracle-ca_us -(at)- oracle -(dot)- com.

[graalvmbot]

Stéphane Micheloud has signed the Oracle Contributor Agreement (based on email address stephane -(dot)- micheloud -(at)- crealp -(dot)- vs -(dot)- ch) so can contribute to this repository.

[michelou]

Partially redundant with #51 and #52; the three PRs should be merged/closed in one step.