"detect shell" test failing on alpine

[pawamoy]

Issue again, sorry 😁 !!

There is just a test failing on Alpine/Busybox, the "detect shell" one, because the ps command returns nothing (surely different/missing options as well).

I'm talking about Alpine because the official bash docker images are based on it :O https://github.com/tianon/docker-bash

I can try and fix it if you're okay!

[juanibiapina]

No need to be sorry! This is great!

I'm ok with busybox support.