This will send a message to a channel when a message is edited, just fill in the " Log channel ID " with the ID of the channel you want to log the edit in.
// authenticates you with the API standard library
// type `await lib.` to display API autocomplete
const lib = require('lib')({token: process.env.STDLIB_SECRET_TOKEN});
const event = context.params.event;
await lib.discord.channels['@0.2.0'].messages.create({
channel_id: `Log channel ID`,
content: `Message edited in <#${context.params.event.channel_id}>`,
});