This is this thinking behind the new numbering scheme, I guess. If a plugin works for Moodle 5.something then it should work for Moodle 5.anything. HQ promise not to let through any breaking changes.
Sorry - that's what I was trying to say but failed miserably. There's no assumption of backward compatibility, either. It's a pain but that's how it works. It's perfectly possible to code around it by checking what version of Moodle is running. However, I suspect that it's more bother than most devs would want to get involved with.
When we hire somebody, the *first* thing I do is to go and find their Github repo. That can be quite revealing.
If you do good work and it's all in there (including how you react to Issues) then clearly point to it on your application. It makes a big difference.
In your case, you may want to think about what "Updated 5 years ago" says about you. Really the same thing that Mary said, above. I know I'm being blunt but you asked...