How to get the horizontal VictoryAxis line to be drawn at a position other than zero?

Question

I have a graph with some bars representing sales and a line representing the goal that each type of sale should reach:

I would like for the horizontal axis line to be at position y=-20 instead of position y=0, without having to add 20 to the y and y0 inside the date array and the tickValues of the VictoryAxis with the goal line.

Is there a way to do this?

demo