sparky src.dest base parameter error

[Zaitsev]

I'm using project full path like this /a/b/c/SRC/d/e/f/SRC/assets
then

    await src('./src/assets/**/*.ttf')
        .dest('./dist/renderer/assets','./SRC')
        .exec()
    ;

dets base path is `./src' and in sparkyChain.runActivities
file path is split into 3 parts

[
'/a/b/c/',
'/d/e/f/'
'/assets/fonts/some.ttf'
]

and s[1] is a wrong base path.
I think is should use just last, not 1 or 2 or any other hard-coded part number.

[charsleysa]

Closed by #1987.