fix artifact filename on arm32

[quantonganh]

#444

[paskal]

@quantonganh I am pretty sure architecture name is arm and not arm32, I never seen builds with arm32 in name anywhere and couldn't find them now. Why do you think this change is necessary?
//cc @umputun

[paskal]

Here is another link where you can see it goes under name arm and not arm32.

[quantonganh]

@paskal You're completely right:

$ go tool dist list | grep arm
linux/arm
linux/arm64

I'm pretty sure I checked the correct architecture name before, but don't know why I just follow the README blindly:

alternatively compile from the sources - make OS=[linux|darwin|windows] ARCH=[amd64,386,arm64,arm32]

It should be fixed to avoid confusion in the future.
Created: #684