webpack.netcore.config.js should pass environment/arguments to webpack.config

**I'm submitting a bug report**

* **Library Version:**
1.2.3

* **Loader/bundler:**
Webpack

**Current behavior:**

Generating a new aurelia project using webpack and .net core produces a webpack.netcore.config.js file that does not pass environment variables or arguments to webpack.config

* **What is the expected behavior?**

The webpack.netcore.config.js should change from this (only relevant portions shown):

```
const webpackConfig = require('./webpack.config');
var originalConfig = webpackConfig({});

module.exports = () => {
let config = originalConfig;
```

to this:

```
const webpackConfig = require('./webpack.config');

module.exports = (env, argv) => {
let config = webpackConfig(env, argv);
```

so that environment variables and arguments are passed.

Inspect the generated webpack.netcore.config.js alongside webpack.config to understand how the .NET Core webpack configuration is assembled. Verify that the generated wrapper forwards environment variables and arguments to webpack.config, then confirm the resulting configuration receives both values when invoked.

Written by the indexing model from the issue text.