Anytime i upgrade OSX to newer version, I get the same issue.
Here is how i solve it every time:
sudo rm -rf /Library/Developer/CommandLineTools
xcode-select --install
That’s it. Now next time you do npm install or yarn it’ll work.
PS: Sometimes you won’t be able to install the command line tool through Xcode-select, for example if you are on beta.
In that case, you should be able to install it manually from here: https://developer.apple.com/download/more/