Preserve strict rule for default export

Author: evenfrost

packages/eslint-config-airbnb/index.js

@@ -1,6 +1,7 @@
 module.exports = {
   'extends': [
     'eslint-config-airbnb/base',
+    'eslint-config-airbnb/rules/strict',
     'eslint-config-airbnb/rules/react',
   ].map(require.resolve),
   rules: {}