iCloud to require app-specific passwords for third party apps
The policy change basically means that users who want to continue using third-party apps with their iCloud account will have to enable two-factor authentication and generate individual passwords for each app.
If you don't already have two-factor authentication enabled on iCloud, do it. Yes, it can be a slight inconvenience at times, but when you weigh that against the value of all the personal data you probably have stored on iCloud, it should be an obvious choice.
Think about what an attacker could do if he gained access to your iCloud account: send and receive messages, view all your photos, or lock you out of your devices, just to name a few possibilities.
So, turn on two-factor authentication.