Version control for Google Apps Script project?

I am using Apps Script to add custom functionality to my Google Sheets:

Trouble is, I would like to keep track of changes made to this code base over time. Git is the obvious solution, but I couldn't find a way to make Apps Script load from a GitHub repository or something like that.

Does Apps Script have this functionality, at all? If not, what's the best way to add version control for an Apps Script project?