Is this project for ANTLR vs IDEA integration dead or alive

[gnom7]

Hey, I see in README it is recommended to use released 0.1 version:

Before 0.1, it was recommended to add this Git repo as a submodule of your own project, or to copy the source files directly.

It is now recommended to use the Maven dependency. The main breaking change is that the base package has been renamed from org.antlr.jetbrains.adaptor to org.antlr.intellij.adaptor

But since there is only one release, produced back in 2019 I'm wondering if it is still the recommended approach or should I rather include source in my own codebase? Project doesn't seem to be abandoned since I see some commits being added over time and 0.1 being released 5 years ago probably lags behind significantly by now.

Is there any resources/guides/documentation concerning ANTLR vs IDEA integration? I'd really prefer to use ANTLR but have hard time figuring out how to integrate it with IDEA/PSI w/o writing and supporting boilerplate code that could have been autogenerated otherwise (org.antlr.jetbrains.sample.psi package in jetbrains-plugin-sample). IDEA GrammarKit seems to generate lots of similar stuff automatically from grammar, but I'd much prefer to stick to ANTLR unless I'm really forced into GrammarKit due to lack of integration support. Is this project maintained? Are there any plans to improve IDEA integration support? How should I get the latest version of this project?