function toNormalizedJsonString(payload) {
    const payloadString = JSON.stringify(payload);
    return payloadString.replace(/[^\\]\\u[\da-f]{4}/g, (s) => {
        return s.substr(0, 3) + s.substr(3).toUpperCase();
    });
}
GitHub sends its JSON with an indentation of 2 spaces and a line break at the end