fix(@angular/cli): add missing webpack-sources dep

`license-webpack-plugin` has a peer dependency on `webpack-sources` that was being satisfied via hoisting.

Fix #8075

Author: filipesilva

package.json

@@ -95,6 +95,7 @@
     "webpack-dev-middleware": "~1.12.0",
     "webpack-dev-server": "~2.7.1",
     "webpack-merge": "^4.1.0",
+    "webpack-sources": "^1.0.0",
     "zone.js": "^0.8.14"
   },
   "devDependencies": {

packages/@angular/cli/models/webpack-configs/production.ts

@@ -9,6 +9,13 @@ import { StaticAssetPlugin } from '../../plugins/static-asset';
 import { GlobCopyWebpackPlugin } from '../../plugins/glob-copy-webpack-plugin';
 import { WebpackConfigOptions } from '../webpack-config';
 
+/**
+ * license-webpack-plugin has a peer dependency on webpack-sources, list it in a comment to
+ * let the dependency validator know it is used.
+ *
+ * require('webpack-sources')
+ */
+
 
 export function getProdConfig(wco: WebpackConfigOptions) {
   const { projectRoot, buildOptions, appConfig } = wco;

packages/@angular/cli/package.json

@@ -79,6 +79,7 @@
     "webpack-dev-middleware": "~1.12.0",
     "webpack-dev-server": "~2.7.1",
     "webpack-merge": "^4.1.0",
+    "webpack-sources": "^1.0.0",
     "zone.js": "^0.8.14"
   },
   "optionalDependencies": {