update webpack to 4.16.5 (#434)

package.json

@@ -68,7 +68,7 @@
     "intersection-observer": "^0.5.0",
     "lodash-es": "^4.17.10",
     "lodash-webpack-plugin": "^0.11.5",
-    "mini-css-extract-plugin": "^0.4.0",
+    "mini-css-extract-plugin": "^0.4.1",
     "mkdirp": "^0.5.1",
     "node-fetch": "^2.1.2",
     "node-sass": "^4.9.0",
@@ -92,9 +92,9 @@
     "svgo": "^1.0.5",
     "timeago.js": "^3.0.2",
     "tiny-queue": "^0.2.1",
-    "uglifyjs-webpack-plugin": "^1.2.6",
+    "uglifyjs-webpack-plugin": "^1.3.0",
     "web-animations-js": "^2.3.1",
-    "webpack": "^4.12.0",
+    "webpack": "^4.16.5",
     "webpack-bundle-analyzer": "^2.13.1",
     "yargs": "^12.0.1"
   },