Pyenv error in Debain 12

**Describe the bug**
setup.sh gives `Error: pyenv not installed` even though there is an install on the machine.
```
❯ pyenv
pyenv 2.3.26
Usage: pyenv []

Some useful pyenv commands are:
...
```

**To Reproduce**
Steps to reproduce the behavior:
1. Run a fresh install of Debian 12
2. Clone LLM-VM repo
3. Run `./setup.sh` within repo folder
4. Go through script
5. after homebrew installs you will get an error:
```* Setting up Pyenv
pyenv found, upgrading to latest version...
Already up-to-date.
Error: pyenv not installed
```
6. process ends.

**Expected behavior**
Install completes

**Desktop**
- OS: Debian 12

**Terminal Output**
[anarch_install_output.txt](https://github.com/anarchy-ai/LLM-VM/files/13763265/anarch_install_output.txt)