support m1 macs

[Brian Dunn]

steps to reproduce

1. :CocInstall coc-fsharp
2. vim foo.fs

Expected

Extension loads and adds language server features

actual

Error message "Platform not Supported" is printed

[Brian Dunn]

I just opened this to draw attention to this pr:#22, which fixed the issue on my machine. thanks @chendesheng

[Yatao Li]

sorry it took soooooo long.... it's done now.