First you need a GitHub account in order to send your translation, or sign in if you already have one.

You can edit the .json file on this link.
Copy the exported text from below, on the linked page overwrite the whole text, and at the bottom of the page you can propose your changes.

Follow this link, name the file as .json, copy the exported text from below, paste it into the textarea on the linked page, and at the bottom of the page you can propose your changes.