Plugin upgrade guide does not mention changes in 2.18 or later (e.g. @rule_helper removal)

[sureshjoshi]

https://www.pantsbuild.org/2.19/docs/writing-plugins/common-plugin-tasks/plugin-upgrade-guide

Upgraded some of my in-repo plugins and got hit with this. It would be cool if the PR label that something is an API change also reminded to update some of these other docs.

I'm casually working on a migrate plugin for in-repo plugins, but it won't be ready for some time.

[huonw]

I'd guess there's even more more changes missing from it than @rule_helper's removal in 2.20, given the most recent release mentioned is 2.17, even in the main branch: https://github.com/pantsbuild/pants/blob/a3eaf7007fcb2d878edd9f08d922799289567c25/docs/docs/writing-plugins/common-plugin-tasks/plugin-upgrade-guide.mdx