chore: upgrade babel to 7.* & support modern browser only

.babelrc

@@ -1,9 +1,14 @@
 {
   "presets": [
-    "stage-2"
+    [
+      "@babel/preset-env",
+      {
+        "targets": "last 1 years"
+      }
+    ]
   ],
   "plugins": [
-    "syntax-dynamic-import",
+    "@babel/plugin-syntax-dynamic-import",
     "lodash"
   ]
 }

package.json

@@ -31,13 +31,13 @@
     "webextension-polyfill": "^0.3.1"
   },
   "devDependencies": {
+    "@babel/core": "^7.4.3",
+    "@babel/plugin-syntax-dynamic-import": "^7.2.0",
+    "@babel/preset-env": "^7.4.3",
     "@cnwangjie/eslint-config": "^1.3.0",
-    "babel-core": "^6.26.3",
     "babel-eslint": "^8.2.6",
-    "babel-loader": "^7.1.4",
+    "babel-loader": "^8.0.5",
     "babel-plugin-lodash": "^3.3.4",
-    "babel-plugin-syntax-dynamic-import": "^6.18.0",
-    "babel-preset-stage-2": "^6.24.1",
     "clean-webpack-plugin": "^0.1.19",
     "copy-webpack-plugin": "^4.5.1",
     "cross-env": "^5.2.0",
@@ -62,5 +62,10 @@
     "vuetify-loader": "^1.1.1",
     "webpack": "^4.6.0",
     "webpack-cli": "^3.1.2"
-  }
+  },
+  "sideEffects": [
+    "**/index.js",
+    "*.css",
+    "*.styl"
+  ]
 }