Add “In Stock” label to variaton swatch

Hi

Can anyone help me figure out how can i add “label” over variation swatch image that shows text if product is on stock?

I almost figured out it if i change plugin core frontend.php file but maybe there is some other way to do it? I would really like to not change plugin file(s)

Example: https://i.imgur.com/N4iyFZU.png