Verify webhook signatures

curl https://api.relay.example/v3/messages \
  -H "Authorization: Bearer $RELAY_KEY" \
  -d channel=sms \
  -d to=+15550100001 \
  -d body="Your code is 482913"

import Relay from '@relay/node';

const relay = new Relay(process.env.RELAY_KEY);
const msg = await relay.messages.create({
  channel: 'sms',
  to: '+15550100001',
  body: 'Your code is 482913',
});
console.log(msg.status); // queued

import os, relay

client = relay.Client(os.environ["RELAY_KEY"])
msg = client.messages.create(
    channel="sms", to="+15550100001", body="Your code is 482913"
)
print(msg.status)  # queued