fix: include plugin with recommended settings (#157)

Ensure eslint-plugin-promise is loaded when using recommended settings.

Author: paleite

index.js

@@ -26,6 +26,7 @@ module.exports = {
   },
   configs: {
     recommended: {
+      plugins: ['promise'],
       rules: {
         'promise/always-return': 'error',
         'promise/no-return-wrap': 'error',