The GitHub disclaimer is meant to say that the code on Develop needs to be used according to the terms of the JUCE 5 licence. And as will be more clear on the website very soon, the Personal license allows to release commercial, closed-source products for free, as long as total revenue is less than $50k yearly, and that a “Made with JUCE” splash screen is added to the app.
The other free option is the GPL one, which continues from JUCE 4 and has no restrictions of funding or splash screen, but requires to distribute the source along with your application.