Add supporting std::filesystem::path

[adamgene]

Support std::filesystem::path, also add testing and cmake. I tested in Ubuntu 24.04 with gcc 13, also 20.04 with gcc 9.4.0 and 8.X. I already use this simplest change from 0.9.10, and used in VS2017~2022/macOS.

[adamgene]

I am not sure which formater should use, It's fine to re-formating by you.

[adamgene]

@metayeti Could you check these changes? I want to discuss another approach. As you can see, path is used in fstream. Is it just necessary to allow the caller to inject the corresponding fstream object into the class that uses it? This can preserve the original use of string and expand the use of fstream; the externally injected fstream can decide whether to support the use of path.

[metayeti]

Hey. This looks proper, thanks for the PR - I will most likely merge it. The only things missing I think is updating version numbers and the changelog - but I can do those. I'll review by the end of the week in more detail

[adamgene]

I tested on both Windows and macOS, and made changes to fix some errors.

[metayeti]

Merged, ty for the contribution! Also sorry you had to wait a bit.

[GXTX]

ftr this ups the requires C++ version to 17 from like 11 or 98...

[metayeti]

ftr this ups the requires C++ version to 17 from like 11 or 98...

True, I didn't really think about that. Doesn't bother me personally but I can see how it may be an issue for some.

[adamgene]

You can use last mINI 0.9.17 that still uses std::string w/o c++17. Maybe add a warning in README.md?

ftr this ups the requires C++ version to 17 from like 11 or 98...

True, I didn't really think about that. Doesn't bother me personally but I can see how it may be an issue for some.

[metayeti]

I'll add a note to releases for now. I may retroactively add one in readme at a next update