Support systems and installs who use experimental/filesystem includes

[jasonroelofs]

Fixes #197

cc @thekendalmiller

[jasonroelofs]

Hmm, that's a lot of failures. Seems to be a change that only works on Mac right now.

[thekendalmiller]

afaict from messing with it this morning and also with your branch, on Ubuntu 22.04, I need to #include <version> or it fails like the github actions are failing.

But it seems <version> was added in c++20 so adding it doesn't help c++17. c++17 will still be broken.

The accepted answer on the stackoverflow is much more complicated. I was trying that but it's failing on c++17. I haven't figure out why yet

[jasonroelofs]

Closing for #201