Update dependencies to v4-latest

Signed-off-by: André Jaenisch <andre.jaenisch@posteo.de>

package.json

@@ -64,13 +64,13 @@
         "copy-webpack-plugin": "^5.1.2",
         "css-loader": "^3.6.0",
         "file-loader": "^5.1.0",
-        "image-webpack-loader": "^5.0.4",
-        "mini-css-extract-plugin": "^0.9.0",
+        "image-webpack-loader": "^5.1.0",
+        "mini-css-extract-plugin": "^0.12.0",
         "nodemon": "^2.0.7",
-        "optimize-css-assets-webpack-plugin": "^6.0.0",
+        "optimize-css-assets-webpack-plugin": "^6.0.1",
         "vue-loader": "^15.9.6",
         "vue-template-compiler": "^2.6.12",
-        "webpack": "^4.45.0",
+        "webpack": "^4.46.0",
         "webpack-cli": "^3.3.12",
         "webpack-merge": "^4.2.2"
     }