GitHub has announced that account passwords will no longer be accepted for authenticating Git operations starting tomorrow. Instead, token-based authentication will be required for all authenticated Git operations. Developers must use a personal access token over HTTPS (recommended) or SSH key by August 13, 2021, to avoid disruption. If you already have two-factor authentication enabled for your GitHub account, you will not be affected by this authentication change. In May, GitHub added support for securing SSH Git operations using FIDO2 security keys.
Source: https://www.bleepingcomputer.com/news/security/github-deprecates-account-passwords-for-authenticating-git-operations/