update dependencies

.babelrc

@@ -1,3 +1,4 @@
 {
-  "presets": ["latest", "stage-0", "react"]
+  "presets": ["@babel/preset-env", "@babel/preset-react"],
+  "plugins": ["@babel/plugin-proposal-class-properties"]
 }

js/client.js

@@ -1,4 +1,4 @@
-import 'babel-polyfill';
+import '@babel/polyfill';
 import React from 'react';
 import { hydrate } from 'react-dom';
 import { createStore, applyMiddleware } from 'redux';

package.json

@@ -19,25 +19,25 @@
   "author": "AOE GmbH <[email protected]> (http://www.aoe.com)",
   "license": "Apache-2.0",
   "dependencies": {
+    "@babel/cli": "^7.10.5",
+    "@babel/core": "^7.10.5",
+    "@babel/node": "^7.10.5",
+    "@babel/polyfill": "^7.10.4",
+    "@babel/preset-env": "^7.10.4",
+    "@babel/preset-react": "^7.10.4",
     "autoprefixer": "7.1.6",
-    "babel-cli": "6.26.0",
-    "babel-core": "6.26.0",
-    "babel-loader": "7.1.2",
-    "babel-polyfill": "6.26.0",
-    "babel-preset-latest": "6.24.1",
-    "babel-preset-react": "6.24.1",
-    "babel-preset-stage-0": "6.24.1",
+    "babel-loader": "^8.1.0",
     "classnames": "2.2.5",
     "cross-env": "^5.1.1",
     "css-mqpacker": "^6.0.1",
     "front-matter": "2.3.0",
     "fs-extra": "4.0.2",
     "highlight.js": "9.12.0",
     "history": "4.7.2",
-    "live-server": "1.2.0",
+    "live-server": "1.2.1",
     "marked": "0.3.18",
     "moment": "2.22.1",
-    "postcss-cli": "4.1.1",
+    "postcss-cli": "^7.1.1",
     "postcss-css-variables": "0.8.0",
     "postcss-custom-media": "^6.0.0",
     "postcss-easy-import": "3.0.0",