Set the es2020 environment by default

Fixes #415
Fixes #406

Author: sindresorhus

Diff for: package.json

@@ -53,7 +53,7 @@
 		"debug": "^4.1.0",
 		"eslint": "^6.8.0",
 		"eslint-config-prettier": "^6.10.0",
-		"eslint-config-xo": "^0.28.0",
+		"eslint-config-xo": "^0.29.0",
 		"eslint-formatter-pretty": "^3.0.1",
 		"eslint-plugin-ava": "^10.0.1",
 		"eslint-plugin-eslint-comments": "^3.1.2",

Diff for: readme.md

@@ -144,7 +144,7 @@ You can configure some options in XO by putting it in package.json:
 ### envs
 
 Type: `string[]`\
-Default: `['node']`
+Default: `['es2020', 'node']`
 
 Which [environments](https://eslint.org/docs/user-guide/configuring#specifying-environments) your code is designed to run in. Each environment brings with it a certain set of predefined global variables.