After August 21, we have to login into github by following these steps

Github Login

Create Personal Access Token on GitHub
From your GitHub account, go to Settings => Developer Settings => Personal Access Token => Generate New Token (Give your password) => Fillup the form => click Generate token => Copy the generated Token, it will be something like ghp_sFhFsSHhTzMDreGRLjmks4Tzuzgthdvfsrta


For Windows OS 
Go to Credential Manager from Control Panel => Windows Credentials => find git:https://github.com => Edit => On Password replace with with your GitHub Personal Access Token => You are Done

If you don’t find git:https://github.com => Click on Add a generic credential => Internet address will be git:https://github.com and you need to type in your username and password will be your GitHub Personal Access Token => Click Ok and you are done

For a Linux-based OS ⤴
For Linux, you need to configure the local GIT client with a username and email address,

$ git config --global user.name "your_github_username"
$ git config --global user.email "your_github_email"
$ git config -l
Once GIT is configured, we can begin using it to access GitHub. Example:

$ git clone https://github.com/YOUR-USERNAME/YOUR-REPOSITORY
> Cloning into `Spoon-Knife`...
$ Username for 'https://github.com' : username
$ Password for 'https://github.com' : give your personal access token here
Now cache the given record in your computer to remembers the token:

$ git config --global credential.helper cache
If needed, anytime you can delete the cache record by:

$ git config --global --unset credential.helper
$ git config --system --unset credential.helper