add ppa for python3.12-dev

.devcontainer/on_create.sh

@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 sudo apt update
 sudo apt install -y netcat
+sudo add-apt-repository -y ppa:deadsnakes/ppa
 curl -sSL https://install.python-poetry.org | python3.12 -
 cat << EOF > config.toml
 [core]