You can fix this by configuring Git to store your password for you.
Make Git store the username and password and it will never ask for them by running:
"git config --global credential.helper store"
or (if using ssh)
"git remote set-url origin git@github.com:username/repo.git"
Make git save the username and password for a session (cache it) by running;
"git config --global credential.helper cache"