build: drop IE 11 support

Author: sectsect

.swcrc

@@ -5,7 +5,7 @@
       "syntax": "ecmascript",
       "jsx": false
     },
-    "target": "es5",
+    "target": "es2015",
     "loose": false,
     "minify": {
       "compress": false,

dist/assets/css/style.css

@@ -12,7 +12,7 @@
     "build": "webpack --env production --mode production",
     "prepare": "husky install"
   },
-  "browserslist": "> 1%, last 2 versions, Firefox ESR, IE >= 11, not Android 4.4.3-4.4.4, not dead",
+  "browserslist": "defaults and supports es6-module",
   "lint-staged": {
     "*": [
       "secretlint"