use jdk17

[Jad-el-khoury]

Description

Migrate to JDK 17.

Checklist

• This PR adds an entry to the CHANGELOG. _See https://keepachangelog.com/en/1.0.0/ for instructions. Minor edits are exempt.
• This PR expects some manual changes to the generated code. The needed changes are detailed in the CHANGELOG entry.
• This PR was tested with at least one code generation, resulting in a working OSLC server.
• This PR does NOT break the user block code

[Jad-el-khoury]

The Jenkins configuration uses JDK 11 & maven 3.8.2.
We will need to update it to use JDK 17 & maven 3.9.6 (the latest available)

[berezovskyi]

I upgraded the JDK in GH actions but it's still using 3.8 Maven. I think the best is to upgrade the mvnw wrapper version and use that instead. Can you do it?

[berezovskyi]

@Jad-el-khoury never mind, just fixed the build with JDK 21 and maven (wrapper) 3.9.6.

[Jad-el-khoury]

@Jad-el-khoury never mind, just fixed the build with JDK 21 and maven (wrapper) 3.9.6.

@berezovskyi ! You have done quite an extensive set of changes on GH Actions. But we are still relying on Jenkins for Lyodesigner.
So, what's next?

1. Update Jenkins?
2. merge this PR?

[berezovskyi]

@Jad-el-khoury I think we shall merge this PR and switch Jenkins to use JDK 17 and latest Maven. If latest Maven in Jenkins is not 3.9.6, then we should switch Jenkins from running mvn to ./mvnw as this PR did.