Add doc goal for scala-maven-plugin

[lostiniceland]

should resolve #22652 (comment)

---

Summary by cubic

Add the doc-jar goal to the scala-maven-plugin for the mill plugin so a ScalaDoc JAR is built during the release. This fixes the missing docs artifact noted in the PR #22652 discussion and unblocks the release.

^{Written for commit 5881a3d. Summary will update on new commits.}

[wing328]

thanks for the quick fix. let's give it a try

[cubic-dev-ai]

No issues found across 1 file

[wing328]

got an error when running mvn clean install

[INFO] --- scala:4.9.5:doc-jar (default) @ openapi-generator-mill-plugin ---
bad option '-doc-format:html' was ignored
bad option '-doc-title' was ignored
source file not found: openapi-generator-mill-plugin 7.19.0 API
2 warnings found
1 error found
[INFO] ------------------------------------------------------------------------

[wing328]

tried various configuration in pom.xml (mill plugin) but no luck

looks like the only choice left is to remove mill plugin from the release and put it in a separate repo for release.

[wing328]

Filed #22736 to remove the plugin

[wing328]

now the publishing job completes without issues: https://github.com/OpenAPITools/openapi-generator/actions/runs/21146336842

[lostiniceland]

This PR should fix it