feat: migrate to react hooks, close #722, close #762 and close #760

During this process, react-styleguidist and other dev deps have been upgraded to latest.

BREAKING CHANGE:

React '>= 16.8' is required.

`{getDataTransferItems}` property has been renamed to `{getFilesFromEvent}`.

.babelrc.js

@@ -0,0 +1,28 @@
+// https://babeljs.io/docs/en/configuration
+const presets = ['@babel/preset-react']
+if (process.env['BABEL_ENV'] === 'es') {
+  presets.unshift(['@babel/preset-env', { modules: false }])
+} else {
+  presets.unshift('@babel/preset-env')
+}
+
+const plugins = [
+  '@babel/plugin-proposal-export-default-from',
+  '@babel/plugin-proposal-logical-assignment-operators',
+  ['@babel/plugin-proposal-optional-chaining', { loose: false }],
+  ['@babel/plugin-proposal-pipeline-operator', { proposal: 'minimal' }],
+  ['@babel/plugin-proposal-nullish-coalescing-operator', { loose: false }],
+  '@babel/plugin-proposal-do-expressions',
+  'add-module-exports'
+]
+
+module.exports = {
+  presets,
+  plugins,
+  env: {
+    test: {
+      presets,
+      plugins: [...plugins, '@babel/plugin-transform-runtime', 'dynamic-import-node']
+    }
+  }
+}

.eslintignore

@@ -1,3 +1,4 @@
 dist/
 coverage/
 typings/*
+!.babelrc.js