You missed the first paragraph: https://home-assistant.io/components/vacuum.xiaomi_miio/#retrieving-the-access-token
This will solve the problem:
sudo apt-get install libffi-dev libssl-dev
You missed the first paragraph: https://home-assistant.io/components/vacuum.xiaomi_miio/#retrieving-the-access-token
This will solve the problem:
sudo apt-get install libffi-dev libssl-dev