fix: Update babel deps to babel 7

Gruntfile.js

@@ -60,7 +60,7 @@ module.exports = function(grunt) {
         options: {
           babelrc: false,
           comments: false,
-          presets: ["babili"],
+          presets: ["minify"],
           sourceMap: true,
         },
         files: {
@@ -72,7 +72,7 @@ module.exports = function(grunt) {
           babelrc: false,
           comments: true,
           plugins: [
-            ["transform-es2015-modules-umd", {
+            ["@babel/transform-modules-umd", {
               globals: {
                 "webextension-polyfill": "browser",
               },

package.json

@@ -17,12 +17,13 @@
   },
   "homepage": "https://github.com/mozilla/webextension-polyfill",
   "devDependencies": {
+    "@babel/core": "^7.0.0",
+    "@babel/plugin-transform-modules-umd": "^7.0.0",
+    "@babel/preset-env": "^7.0.0",
+    "@babel/register": "^7.0.0",
     "async-wait-until": "^1.1.5",
-    "babel-core": "^6.26.3",
     "babel-eslint": "^8.0.1",
-    "babel-plugin-transform-es2015-modules-umd": "^6.24.1",
-    "babel-preset-babili": "^0.0.10",
-    "babel-preset-es2017": "^6.24.1",
+    "babel-preset-minify": "^0.5.1",
     "browserify": "^16.2.2",
     "chai": "^3.5.0",
     "chromedriver": "^78.0.1",
@@ -32,7 +33,7 @@
     "geckodriver": "^1.11.2",
     "global-replaceify": "^1.0.0",
     "grunt": "^1.0.1",
-    "grunt-babel": "^6.0.0",
+    "grunt-babel": "^8.0.0",
     "grunt-contrib-concat": "^1.0.1",
     "grunt-coveralls": "^1.0.1",
     "grunt-replace": "^1.0.1",

test/mocha-babel.js

@@ -1,3 +1,7 @@
-require("babel-core/register")({
-  presets: ["es2017"],
+require("@babel/register")({
+  presets: [["@babel/env", {
+    targets: {
+      node: "current",
+    },
+  }]],
 });