Zeokat I do agree that it does take extra memory, I believe it is composer though.
I have a bash script i run before hand that backs it up and also adds 1GB of swap, because i hate when it fails.
The swap part of that script:
sudo fallocate -l 1G /swapfile
sudo chmod 600 /swapfile
sudo mkswap /swapfile
sudo swapon /swapfile
echo 'on restart swap will disappear'
I also want to say, that I was able to upgrade fine, everything looks to be working as expected, thanks team!!!