Update contributing

Author: Stuk

documentation/contributing.md

@@ -66,8 +66,9 @@ If you have tested bug fixes or new features, you can open a
 1. Run `npm test`
     * Locally open http://localhost:8080/test/
     * Or use the SauceLabs configuration above
-2. Update `JSZip.version` in `index.js`
+2. Update `JSZip.version` in `index.js` and in `package.json`
 3. Run `grunt` to generate the new dist files
+    * undo the package.json change, it was just needed to replace the `__VERSION__` in the header
 4. Update CHANGES.md
 5. Run `npm version ...` where `...` is `major`, `minor`, or `patch`
 6. Run npm publish