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)

```

Reproduziere `npx git-cz` aus Git Bash unter Windows mit dem im Bericht angegebenen Befehl und der dort angegebenen Ausgabe. Untersuche `bin/git-cz.js` und den in `dist/cli.js` gezeigten `createState`-Pfad und ermittle anschließend, ob der Fehler bei der npm-Installation oder bei der Suche nach dem Git-Root zuerst auftritt. Als erledigt gilt die Aufgabe, wenn der Befehl aus einem Git-Repository ohne einen der beiden gemeldeten Fehler erfolgreich ausgeführt wird.

Vom Indexierungsmodell aus dem Issue-Text verfasst.