I know it's been a while since I came here. Sorry I'm working a lot to not fail my exams for my engineer studies. I totally remade the plugin so you may want to redownload it, but warning, your old projects using it may not work anymore. Sorry about that :(.
Laurent About adapting it to Construct 3, I don't really know, since I don't use the soft and don't know the way to convert plugins.
Also the big thing about the update is (maybe ? It's been a while since I worked on it) the fact that you can update it by yourself since the ink engine by itself is in a different file. So when there's an update, you can go to https://github.com/y-lohse/inkjs/releases and replace it in the plugin's folder on your PC.
Have a good day !!!