fix(ci): ignore npm cache in AppVeyor
fix(ci): ignore npm cache in AppVeyor

Often `npm install` in AppVeyor fails with error:

```
Error: EPERM: operation not permitted, rename
'C:\Users\appveyor\AppData\Roaming\npm-cache\core-js\2.4.1\package.tgz.2
558232453' ->
'C:\Users\appveyor\AppData\Roaming\npm-cache\core-js\2.4.1\package.tgz'
npm ERR!     at Error (native)
```

To ignore npm cache need run `npm cache clean`.

blond/tartifacts