HTTPS transport with OAuth tokens can be used as a replacement for deploy keys. This makes it easier to build and deploy projects through scripting.

Step 1: Get an OAuth token

Create a token via command line or web flow. You'll need repo scope to access private repositories.

Step 2: Clone a repository

Once you have a token, you can use this as your username when using Git over HTTPS:

git clone https://github.com/username/repo.git
Username: your_token 
Password: 

When prompted, you can either use a blank password or the value x-oauth-basic if your client requires a password.

To avoid the prompts, you can use git password caching.

Warning: Tokens have read/write access and should be treated the same way as passwords. Putting the token in the clone URL when cloning or adding a remote will result in git writing it to the .git/config file in plain text.