Run these to find the new executable you built (and it looks like you have done that step)
$(find $HOME/git/upgrade/dist-newstyle/build -type f -name "cardano-cli") version
$(find $HOME/git/upgrade/dist-newstyle/build -type f -name "cardano-node") version
But now you need to copy the executable over:
sudo cp $(find $HOME/git/upgrade/dist-newstyle/build -type f -name "cardano-cli") /usr/local/bin/cardano-cli
sudo cp $(find $HOME/git/upgrade/dist-newstyle/build -type f -name "cardano-node") /usr/local/bin/cardano-node
You can also follow my upgrade guide. https://forum.cardano.org/t/update-to-8-1-1-for-coincashew-users/ (just change the 8.1.1 to 8.1.2 when you set the flag, obviously).