Update usage instructions to remove Java setup

[schivmeister]

Currently the README instructions mention the following:

  - uses: actions/setup-java@v4
    with:
      distribution: temurin
      java-version: 17 # Jena4 requires Java 11+

This setup for Java is redundant and therefore not required as the Ubuntu runners come with Java by default. See actions/runner-images#9848 (default changed from 11 to 17 from 22.04 to 24.04) and https://github.com/actions/runner-images/blob/main/images/ubuntu/Ubuntu2004-Readme.md (it appears even 20.04 had 11 as default).

Thanks for this maintaining this Action!

[foooomio]

Thank you for pointing it out.

That's definitely correct but ubuntu-22.04, which was ubuntu-latest until a few months ago, uses Java 11 by default, even though Jena5 requires Java 17+. There should be documentation on how to change the Java version, as some users are unaware of the correspondence between the runners and tool versions.

[schivmeister]

Indeed, but I saw that there is an input for the Jena version:

jena-version: Optional. The version of Apache Jena to be installed. Example: 4.1.0. Defaults to latest.

So on older runners the instructions could further specify how to fetch an older version of Jena compatible with the Java version on that runner.

[foooomio]

Doesn't make sense. Why limit the Jena version when setup-java will solve the problem?