As long as you (a) don't publish your project as open source (i.e., keep it private on GitHub) or (b) put a really big fat warning in the README that it's an experiment that may be abandoned at any time and nobody should rely on it, I guess it's ok... but who really does that?
Publishing a project does not mean you're obligated to maintain it. There is no need to explicitly write this in documentation either. Nobody is obligated to work for free. If people expect to rely on developers, they need to hire them.
