testing suite is broken when there are no old python versions in the path

[PhilTaken]

λ ❱ bin/tox
py36 create: /<redacted>/flyingcircusio/batou/.tox/py36
SKIPPED: InterpreterNotFound: python3.6
py37 create: /<redacted>/flyingcircusio/batou/.tox/py37
SKIPPED: InterpreterNotFound: python3.7
py38 create: /<redacted>/flyingcircusio/batou/.tox/py38
SKIPPED: InterpreterNotFound: python3.8
py39 create: /<redacted>/flyingcircusio/batou/.tox/py39
SKIPPED: InterpreterNotFound: python3.9
pre-commit create: /<redacted>/flyingcircusio/batou/.tox/pre-commit
SKIPPED: InterpreterNotFound: python3.9
______________________ summary ______________________
SKIPPED:  py36: InterpreterNotFound: python3.6
SKIPPED:  py37: InterpreterNotFound: python3.7
SKIPPED:  py38: InterpreterNotFound: python3.8
SKIPPED:  py39: InterpreterNotFound: python3.9
SKIPPED:  pre-commit: InterpreterNotFound: python3.9
  congratulations :)
λ ❱

after a fresh ./develop.sh

relevant python versions in my path:

λ ❱ ls -H $PATH 2>/dev/null | grep python
nvim-python3
python
python-config
python3
python3-config
python3.10
python3.10-config
python3
λ ❱

I propose the test suite should fall back to python or python3 if the above versions are not found