fix(cli): run npm init -y if needed

Author: EvanLovely

README.md

@@ -30,7 +30,7 @@ The below assumes a new directory and project is required. This is likely what y
     ```bash
     mkdir new-project
     cd new-project
-    npm init -y && npx @pattern-lab/cli -c patternlab init
+    npx @pattern-lab/cli -c patternlab init
     ```
     > If you get an error stating that `npx` is not installed, ensure you are on `npm 5.2.0` or later by running `npm -v` or install it globally with `npm install -g npx`. [Learn more about npx.](https://medium.com/@maybekatz/introducing-npx-an-npm-package-runner-55f7d4bd282b)
 1. Follow the on-screen prompts to choose your Edition and a Starterkit should you want one.

packages/cli/bin/scaffold.js

@@ -1,5 +1,7 @@
 'use strict';
 const path = require('path');
+const execa = require('execa');
+const fs = require('fs');
 const wrapAsync = require('./utils').wrapAsync;
 const mkdirsAsync = require('./utils').mkdirsAsync;
 
@@ -14,6 +16,9 @@ const mkdirsAsync = require('./utils').mkdirsAsync;
  */
 const scaffold = (projectDir, sourceDir, publicDir, exportDir) =>
   wrapAsync(function*() {
+    if (!fs.existsSync(path.resolve(projectDir, 'package.json'))) {
+      execa.sync('npm', ['init', '-y']);
+    }
     /**
      * Create mandatory files structure
      * 1. Create project source directory