Git bash on windows: cannot read property 'get' of undefined

Currently I get this error when running git-cz on a windows system:
```
Martin Muzatko@martin MINGW64 ~/dev/bitbucket/sicon (docker)
$ npx git-cz
Error: EPERM: operation not permitted, mkdir 'C:\Users\Martin'
TypeError: Cannot read property 'get' of undefined
at errorHandler (C:\Program Files\nodejs\node_modules\npm\lib\utils\error-handler.js:205:18)
at C:\Program Files\nodejs\node_modules\npm\bin\npm-cli.js:83:20
at cb (C:\Program Files\nodejs\node_modules\npm\lib\npm.js:224:22)
at C:\Program Files\nodejs\node_modules\npm\lib\npm.js:262:24
at C:\Program Files\nodejs\node_modules\npm\lib\config\core.js:81:7
at Array.forEach ()
at C:\Program Files\nodejs\node_modules\npm\lib\config\core.js:80:13
at f (C:\Program Files\nodejs\node_modules\npm\node_modules\once\once.js:25:25)
at afterExtras (C:\Program Files\nodejs\node_modules\npm\lib\config\core.js:178:20)
at C:\Program Files\nodejs\node_modules\npm\node_modules\mkdirp\index.js:47:53
at C:\Program Files\nodejs\node_modules\npm\node_modules\graceful-fs\polyfills.js:284:29
at FSReqWrap.oncomplete (fs.js:170:21)
C:\Program Files\nodejs\node_modules\npm\lib\utils\error-handler.js:205
if (npm.config.get('json')) {
^

TypeError: Cannot read property 'get' of undefined
at process.errorHandler (C:\Program Files\nodejs\node_modules\npm\lib\utils\error-handler.js:205:18)
at process.emit (events.js:180:13)
at process._fatalException (bootstrap_node.js:431:27)
Install for prefix@latest failed with code 7
C:\Users\Martin Muzatko\AppData\Roaming\npm\node_modules\git-cz\bin\git-cz.js
The system cannot find the path specified.
× fatal Error: Could not find Git root folder.
at createState (C:\Users\Martin Muzatko\AppData\Roaming\npm\node_modules\git-cz\dist\cli.js:202:11)
at main (C:\Users\Martin Muzatko\AppData\Roaming\npm\node_modules\git-cz\dist\cli.js:105:19)
at Object.2../createState (C:\Users\Martin Muzatko\AppData\Roaming\npm\node_modules\git-cz\dist\cli.js:158:1)
at o (C:\Users\Martin Muzatko\AppData\Roaming\npm\node_modules\git-cz\dist\cli.js:1:327)
at r (C:\Users\Martin Muzatko\AppData\Roaming\npm\node_modules\git-cz\dist\cli.js:1:493)
at Object. (C:\Users\Martin Muzatko\AppData\Roaming\npm\node_modules\git-cz\dist\cli.js:1:522)
at Module._compile (module.js:649:30)
at Object.Module._extensions..js (module.js:660:10)
at Module.load (module.js:561:32)
at tryModuleLoad (module.js:501:12)

```

Reproduce `npx git-cz` desde Git Bash en Windows usando el comando y la salida del informe. Inspecciona `bin/git-cz.js` y la ruta de `createState` mostrada en `dist/cli.js`; después, determina si el fallo de instalación de npm o la búsqueda de la raíz de Git es el primer fallo. Se considera terminado cuando el comando se ejecuta correctamente desde un repositorio de Git sin ninguno de los dos errores indicados.

Escrito por el modelo de indexación a partir del texto del issue.