new_variant: correct path in README.md

Fix an error in code snippets that shows an incorrect path for
new_variant.py.

BUG=None
TEST=verify that the path in the code snippets is correct

Change-Id: Ie34816ce9360037c876d3a2654d75eb40f2cab51
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/2235894
Tested-by: Paul Fagerburg <pfagerburg@chromium.org>
Reviewed-by: Henry Sun <henrysun@google.com>
Commit-Queue: Paul Fagerburg <pfagerburg@chromium.org>
1 file changed