fix jsonPath in ComposerScriptsConfigurator::update

[klkvsk]

Fixes #1010

flex/src/Configurator/ComposerScriptsConfigurator.php

Line 52 in bec213c

$jsonPath = ltrim(str_replace($recipeUpdate->getRootDir(), '', $json->getPath()), '/\\');

In case when root dir = ".", it replaces the dot in filename, and then applying the patch is broken with:

NOTE:
  The file composerjson was not updated because it doesn't exist in your app.

Change to using Path::makeRelative for proper result.