sudo pip3 freeze | awk -F "==" '{print $1}' | xargs sudo pip3 install --upgrade
I've struggled with this before. So, I'm writing it down for future reference.
AFAIK, pip doesn't support upgrading packages en-masse. But with shell piping, we can achieve the equivalent of
pip install --upgrade ALL.
And, its usually the 2nd part of the pipe that I get stuck on, because I'm not very AWKward (hehe, bad pun for myself).