Switch from buble to babel for ES5 transpilation (close #8065)

babel.config.json

@@ -0,0 +1,8 @@
+{
+  "presets": [
+    [
+      "@babel/env"
+    ]
+  ],
+  "compact": false
+}

config/rollup.config.legacy.js

@@ -1,5 +1,5 @@
 /* eslint-disable no-console */
-import buble from '@rollup/plugin-buble';
+import babel from '@rollup/plugin-babel';
 import commonjs from '@rollup/plugin-commonjs';
 import includePaths from 'rollup-plugin-includepaths';
 import json from '@rollup/plugin-json';
@@ -28,10 +28,8 @@ export default {
     nodeResolve({ dedupe: ['object-inspect'] }),
     commonjs(),
     json({ indent: '' }),
-    buble({
-      transforms: {
-        dangerousForOf: true
-      }
+    babel({
+      babelHelpers: 'bundled'
     })
   ]
 };

package.json

@@ -65,13 +65,15 @@
     "which-polygon": "2.2.0"
   },
   "devDependencies": {
+    "@babel/core": "^7.11.6",
+    "@babel/preset-env": "^7.11.5",
     "@fortawesome/fontawesome-svg-core": "^1.2.32",
     "@fortawesome/free-brands-svg-icons": "~5.15.1",
     "@fortawesome/free-regular-svg-icons": "~5.15.1",
     "@fortawesome/free-solid-svg-icons": "~5.15.1",
     "@ideditor/temaki": "~4.2.0",
     "@mapbox/maki": "^6.0.0",
-    "@rollup/plugin-buble": "^0.21.0",
+    "@rollup/plugin-babel": "^5.2.1",
     "@rollup/plugin-commonjs": "^15.0.0",
     "@rollup/plugin-json": "^4.0.1",
     "@rollup/plugin-node-resolve": "~8.1.0",