Personally, I tend to post the change in a comment on the issue that it fixes. I don't generally bother with doing a formal PR, since that would mean setting up the repo in a dev environment, branching, etc. and would be a bunch of extra work.
Locally, I just make the change and check it in to my project.
Here's an example:
https://github.com/xwpongithub/vue-range-slider/issues/3#iss...