quick check proxy list from a file

Hello! I think it's will be useful for quickly checking and verify your proxy list from a file. I'm also available for any suggestion. https://github.com/asm-jaime/go-proxycheck

I did a quick check and it feels a bit clunky. I have to head out shortly, when I return - I'll take some time to give a proper code review

I will appreciate it if you do.