There is no error. This is not an error. It is a notice. Nothing is broken. Go on with what you are doing.
There is nothing wrong with your system. All it is doing is notifying you that the pip that you currently have installed has a newer version available for upgrade. pip is the application used to download Python library packages.
To upgrade to the latest pip application, in the terminal, just type:
python -m pip install --upgrade pip
After having done so, your pip will be upgraded and this message should go away.