Update needed: yarn repo key, katana branch name, certs generation folder patch, pip binary location patch

[lekalmouk]

Hi.
Update provision.sh with:

Line 6, add

curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -

Line 70, add

sudo mkdir /etc/samurai.d/certs

Line 82, add:

sudo ln -s /usr/local/bin/pip3.8 /usr/bin/pip3.8
sudo pip3.8 install --upgrade pip
sudo chmod -x /etc/systemd/system/samurai-katana.service

Line 89, change

BRANCH="master"

To

BRANCH="main"