Rokit should warn if using an outdated version

I recently came across this where I initially thought there was an issue with something I was downloading but the issue was that my rokit was out-of-date. I only found out when I created an issue and got a response from a maintainer. I propse that when running `rokit add` or `rokit install` that rokit checks version and if you are on an outdated version it should warn you and advise you to run `rokit self-update`.