Update tofu to work with deb12

Signed-off-by: Arnaud M <arnaud.choupinette@mailops.fr>

terraform/training/files/install-demo-flask.sh

@@ -1,8 +1,10 @@
 #!/bin/bash
 apt-get update
-apt-get -y install python3-pip git
+apt-get -y install python3-pip git python3-venv
 git clone https://github.com/arnaudmorin/demo-flask /opt/demo-flask
-pip3 install -r /opt/demo-flask/requirements.txt
+python3 -m venv /opt/demo-flask-venv
+/opt/demo-flask-venv/bin/pip install -r /opt/demo-flask/requirements.txt
+sed -i -r 's|^python3|/opt/demo-flask-venv/bin/python|' /opt/demo-flask/start.sh
 cp /opt/demo-flask/demo-flask.service /etc/systemd/system/
 systemctl enable demo-flask.service
 systemctl daemon-reload