Configure Browserslist for JS supported browsers

The default browsers that load our CSS differ to those that run our JavaScript, so we don’t need Babel transforms for IE11 and other legacy browsers

We’ll start by targetting `supports es6-module` and can optionally exclude Babel transforms or plugins as required, should we prefer feature detection instead

docs/examples/webpack/.browserslistrc

@@ -1,12 +1,5 @@
-> 0.1% in GB and not dead
-last 6 Chrome versions
-last 6 Firefox versions
-last 6 Edge versions
-last 2 Samsung versions
-Firefox ESR
-Safari >= 11
-iOS >= 11
-ie 11
+[javascripts]
+supports es6-module
 
 [stylesheets]
 > 0.1% in GB and not dead

docs/examples/webpack/babel.config.js

@@ -5,14 +5,14 @@
  */
 module.exports = function (api) {
   const browserslistEnv = !api.env('test')
-    ? 'production'
+    ? 'javascripts'
     : 'node'
 
   return {
     presets: [
       ['@babel/preset-env', {
         browserslistEnv,
-        loose: browserslistEnv === 'production',
+        loose: browserslistEnv === 'javascripts',
 
         // Transform ES modules for Node.js
         modules: browserslistEnv === 'node' ? 'auto' : false

packages/govuk-frontend-review/.browserslistrc

@@ -1,12 +1,5 @@
-> 0.1% in GB and not dead
-last 6 Chrome versions
-last 6 Firefox versions
-last 6 Edge versions
-last 2 Samsung versions
-Firefox ESR
-Safari >= 11
-iOS >= 11
-ie 11
+[javascripts]
+supports es6-module
 
 [stylesheets]
 > 0.1% in GB and not dead

packages/govuk-frontend/.browserslistrc

@@ -1,15 +1,8 @@
 # This list builds on the GOV.UK service manual's browser testing recommendations
 # https://www.gov.uk/service-manual/technology/designing-for-different-browsers-and-devices
 
-> 0.1% in GB and not dead
-last 6 Chrome versions
-last 6 Firefox versions
-last 6 Edge versions
-last 2 Samsung versions
-Firefox ESR
-Safari >= 11
-iOS >= 11
-ie 11
+[javascripts]
+supports es6-module
 
 [stylesheets]
 > 0.1% in GB and not dead