(Blint is the in-tree tool factored into its own npm package.)

Node provides some cross-platform utility methods to enable safe
path traversal.

This change merely swaps out a hardcoded '/' (unix path separator)
to use one of these methods.

An alternative strategy would be to use the constant 'path.sep' but
this felt 'cleaner'.

Signed-off-by: ciaranj <ciaranj@gmail.com>