restore skip-code-generation property usage

[hboutemy]

restore property usage introduced in 1ff5895
but removed in #1172

necessary to rebuild the reference release published to Maven Central, that is build with the generation profile activated, which adds dependencies (even if provided)

see jvm-repo-rebuild/reproducible-central#4800

[chrisdutz]

Admittedly I don't quite understand that change ... the plugin is only used (except for the mspec-tests) inside the update-generated-code profile. Also do we run the code generation in a preparation step before starting the release:prepare & repease:perform steps. As far as I can see it, only the "apache-release" profile is enabled when building the jars for maven central. (That might have been different in the past, but should be that way now)

Could you elaborate a bit on why this change is needed? Even if it's a trivial change, I can see "skip-code-generation" is being defined and set to false, but it's not used anywhere, so removing the property all together seems to make more sense.

[hboutemy]

perhaps I did a mistake when deducting root cause of the difference https://github.com/jvm-repo-rebuild/reproducible-central/blob/master/content/org/apache/plc4x/plc4x/plc4x-parent-0.13.1.diffoscope

the fact is that for now, I can't find a way to rebuild plc4x 0.13.1 and get the same output (beyond the small develocity-workspace-id difference)

you know the build better than me, perhaps the root cause is something else that will be easier for you to analyze

[chrisdutz]

It looks a bit like one was built with "with-dotnet" and "with-python" enabled and one without. But no idea why the mvn:commons-io/commons-io/2.20.0 is added.