fix: update webpack dependencies (#675)

fixes #674

package.json

@@ -78,21 +78,21 @@
     "semver": "5.4.1",
     "shelljs": "0.6.0",
     "tapable": "1.0.0",
-    "webpack": "~4.6.0",
-    "webpack-cli": "~2.1.3",
-    "webpack-bundle-analyzer": "~2.13.0",
-    "webpack-sources": "~1.1.0",
+    "webpack": "~4.20.2",
+    "webpack-cli": "~3.1.1",
+    "webpack-bundle-analyzer": "~3.0.2",
+    "webpack-sources": "~1.3.0",
     "clean-webpack-plugin": "~0.1.19",
-    "copy-webpack-plugin": "~4.5.1",
+    "copy-webpack-plugin": "~4.5.2",
     "raw-loader": "~0.5.1",
-    "css-loader": "~0.28.11",
+    "css-loader": "~1.0.0",
     "nativescript-worker-loader": "~0.9.0",
     "extract-text-webpack-plugin": "~3.0.2",
     "uglifyjs-webpack-plugin": "~1.2.5",
     "@angular-devkit/core": "~0.8.1",
-    "resolve-url-loader": "~2.3.0",
-    "awesome-typescript-loader": "~5.0.0",
-    "sass-loader": "~7.0.1"
+    "resolve-url-loader": "~3.0.0",
+    "awesome-typescript-loader": "~5.2.1",
+    "sass-loader": "~7.1.0"
   },
   "devDependencies": {
     "@ngtools/webpack": "~6.2.0",