Upgrade instructions for non-docker setup omits to rm the API zip file

For non docker setup, the upgrade instruction for the API is as follows:

# this assumes you want to upgrade to version "1.0"
export FUNKWHALE_VERSION="1.0"
cd /srv/funkwhale

# download more recent API files
sudo -u funkwhale curl -L -o "api-$FUNKWHALE_VERSION.zip" "https://dev.funkwhale.audio/funkwhale/funkwhale/-/jobs/artifacts/$FUNKWHALE_VERSION/download?job=build_api"
sudo -u funkwhale unzip "api-$FUNKWHALE_VERSION.zip" -d extracted
sudo -u funkwhale rm -rf api/ && sudo -u funkwhale mv extracted/api .
sudo -u funkwhale rm -rf extracted

# update os dependencies
sudo api/install_os_dependencies.sh install
sudo -u funkwhale -H -E /srv/funkwhale/virtualenv/bin/pip install -r api/requirements.txt

# collect static files
sudo -u funkwhale -H -E /srv/funkwhale/virtualenv/bin/python api/manage.py collectstatic --no-input

# stop the services
sudo systemctl stop funkwhale.target

# apply database migrations
sudo -u funkwhale -H -E /srv/funkwhale/virtualenv/bin/python api/manage.py migrate

# restart the services
sudo systemctl start funkwhale.target

Only the extracted/ directory is removed. api-$FUNKWHALE_VERSION.zip should be removed as well after it is extracted.