No, this is not something Drone would handle. You would have to write a small, standalone microservice that would be capable of receiving and parsing github webhooks. If if receives a user removal webhook from github, you could use the Drone API to remove the user from Drone.
Below is some example code that demonstrates how this might work.
First you would need to deploy this microservice somewhere with a public address so that it can receive GitHub wehbooks. Next you would create webhook in your organization settings screen in GitHub where the payload url is the public address of your microservice. Finally, you would configure the webhook to only trigger for Organization events (select the “Let me select individual events” radio button and check the “Organizations” checkbox that appears below).
Disclaimer that the below example is pseudocode and is non-functional; you will probably need to modify the code to get it working.
const axios = require('axios')
const express = require('express')
const app = express()
const port = 3000
const token = 'your-drone-access-token'
app.use(express.json());
app.post('/', (req, res) => {
if (req.body.removed) {
axios.delete(`https://drone.company.com/api/users/${req.body.member}?access_token=${token}`)
}
})
app.listen(port, () => {
console.log(`Example microservice listening at http://localhost:${port}`)
})