Update genjavadoc-plugin to 0.18_2.13.8

[scala-steward]

Updates com.typesafe.genjavadoc:genjavadoc-plugin from 0.18_2.12.15 to 0.18_2.13.8.
GitHub Release Notes - Version Diff

I'll automatically update this PR to resolve conflicts as long as you don't change it yourself.

If you'd like to skip this version, you can just close this PR. If you have any feedback, just mention me in the comments below.

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Ignore future updates

Add this to your .scala-steward.conf file to ignore future updates of this dependency:

updates.ignore = [ { groupId = "com.typesafe.genjavadoc", artifactId = "genjavadoc-plugin" } ]

labels: library-update, commit-count:1

[stevedlawrence]

I think we don't actually want to merge this? The CI tests pass, but I assume we want to stick with the version of genjavadoc that matches our scala version (2.12.15)?

In fact, looking at the GenJavaDocPlugin, I wonder if we should even being including the scala version in the value of unidocGenjavadocVersion? Looking at this file:

https://github.com/sbt/sbt-unidoc/blob/master/src/main/scala/sbtunidoc/GenJavadocPlugin.scala

The setting defaults to just "0.18" and uses crossVersion to get the right Scala version. Seems like maybe we should change this back to just "0.18"?

[tuxji]

I looked at sbt/sbt-unidoc#110, https://github.com/sbt/sbt-unidoc, and https://github.com/apache/daffodil/blame/main/daffodil-japi/build.sbt to determine why we need that unidocGenjavadocVersion line (we need it because the old default, 0.15, doesn't work anymore, a PR changed it to 0.18 in the sbt-unidoc repo only yesterday, and a new sbt-unidoc release hasn't been made yet), whether we should keep that unidocGenjavadocVersion line (yes because the default in the last released sbt-unidoc version is still 0.15), when we first added that unidocGenjavadocVersion line (in your PR #398 almost two years ago), and why it changed to include a Scala cross version (blame Scala Steward for adding it in PR #634). I agree you can change it back to "0.18" and leave it there, but Scala Stewart may add a new Scala cross version to it again in the future. If you change that line anyway, you probably want to add a comment to remind us that the cross version shouldn't be needed and find a way to tell Scala Stewart not to add a cross version again (if possible).

[stevedlawrence]

Thanks for confirming my thinking. Looking at the scala-steward configuration options, nothing jumps out at me as a way to prevent this. And we don't want to ignore this line altogether since we'll still want PRs if genjavadoc creates a new release.

I've fixed this and added a comment so we hopefully catch it if Scala Steward tries this again.

[tuxji]

+1

I love the new comment. Well said!

[stevedlawrence]

+1