You’re always welcome to submit pull requests to GitHub, sure! But if all you are doing is changing a language file, that wouldnt be anything that is a new feature or a fix for WC Vendors, so I’m not sure that’s the right thing to do. The language files you use would just go in /wp-content/languages/ so they are not overwritten.
https://codex.wordpress.org/Installing_WordPress_in_Your_Language