When you cribbed the code you should have completely understood what exactly the package was doing, and why, and known what issues it would have had. Since it's a one-liner, it is transparent. Since it is without dependencies, it is unlikely to fail on old code. So it's unlikely to have existing issues and unlikely to develop new issues.

Of course, if you end up using new features of the language in your code, it may fail on that, but the risk old stuff failing should have already been factored in when you decided to upgrade. In fact, the one-liner solves this better since you decide the pace of adaptation of your one-liner to the new features, not the package maintainer.