fs option

[SuperchupuDev]

hi! a fs option would be great to have to allow users to provide their own fs implementations - it was requested in SuperchupuDev/tinyglobby#81 (comment) however that can't be added to tinyglobby without it being added here first. i can try to pr the option, but first i'd like to know if @thecodrr agrees with the existence of such an option

[thecodrr]

That's been on my to-do for a long time. Feel free to open a PR. Shouldn't be too hard to add.