Update dependencies (#9)

Update 'terser-webpack-plugin' and 'webpack-dev-server'

Author: calebmshafer

packages/react-scripts/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@bentley/react-scripts",
-  "version": "3.4.1",
+  "version": "3.4.2",
   "description": "iModel.js configuration and scripts for Create React App.",
   "repository": {
     "type": "git",
@@ -79,12 +79,12 @@
     "speed-measure-webpack-plugin": "^1.3.1",
     "style-loader": "0.23.1",
     "svg-sprite-loader": "4.2.1",
-    "terser-webpack-plugin": "2.3.5",
+    "terser-webpack-plugin": "3.0.7",
     "ts-jest": "^24.2.0",
     "ts-pnp": "1.1.6",
     "url-loader": "2.3.0",
     "webpack": "4.42.0",
-    "webpack-dev-server": "3.10.3",
+    "webpack-dev-server": "3.11.0",
     "webpack-filter-warnings-plugin": "^1.2.1",
     "webpack-manifest-plugin": "2.2.0",
     "workbox-webpack-plugin": "4.3.1"