➖ remove dependency on node:path; reinvent wheel

[ctcpip]

resolves #111 (potentially)

I'm not a huge fan of reinventing the wheel here, but it's one possible solution

[pliashkou]

It will help to fix https://github.com/jshttp/mime-types/issues/157

[UlisesGascon]

@ctcpip let me know if you want me to include this in the next release :thinking:

[utopyin]

using extname.js as a patch right now, would love for this to be merged in the next release!