Add Social Icon

Hello everyone!

Im created a sub-theme using Belgrade as a base theme, and I would like to add to social menu the icon of "whatsapp".
I have tried to follow those steps on ( https://www.drupal.org/project/belgrade/issues/3097852 → ), but couldnt get it...
I placed the SVG icon on Belgrade/icons folder, then when I try to run npm run icons it returns that icons does not exists... checking with npm run, it says exits only icons-sprite.. trying to run npm run icons-sprite I receive this message:

> belgrade@1.0.9 icons-sprite
> svg-sprite --svg-namespace-classnames false --symbol --symbol-dest . --symbol-sprite images/belgrade-icons.svg icons/*.svg
sh: 1: svg-sprite: not found

Could you please help me?

Thank you very much in advance!

Camila F.