lint: Sync configuration with gjs

gjs updated its eslint configuration, so sync our copy.

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1498

lint/eslintrc-gjs.yml

@@ -1,4 +1,5 @@
 ---
+# SPDX-License-Identifier: MIT OR LGPL-2.0-or-later
 env:
   es6: true
 extends: 'eslint:recommended'
@@ -24,7 +25,9 @@ rules:
   #     allow: [^vfunc_, ^on_, _instance_init]
   comma-dangle:
     - error
-    - always-multiline
+    - arrays: always-multiline
+      objects: always-multiline
+      functions: never
   comma-spacing:
     - error
     - before: false
@@ -106,15 +109,15 @@ rules:
   no-prototype-builtins: 'off'
   no-restricted-properties:
     - error
+    - object: Lang
+      property: copyProperties
+      message: Use Object.assign()
     - object: Lang
       property: bind
       message: Use arrow notation or Function.prototype.bind()
     - object: Lang
       property: Class
       message: Use ES6 classes
-    - object: imports
-      property: mainloop
-      message: Use GLib main loops and timeouts
   no-restricted-syntax:
     - error
     - selector: >-
@@ -130,6 +133,8 @@ rules:
         BlockStatement[body.length=1]
         CallExpression[arguments.length=0][callee.object.type="Super"][callee.property.name="_init"]
       message: _init() that only calls super._init() is unnecessary
+    - selector: BinaryExpression[operator="instanceof"][right.name="Array"]
+      message: Use Array.isArray()
   no-return-assign: error
   no-return-await: error
   no-self-compare: error
@@ -166,6 +171,9 @@ rules:
   object-shorthand: error
   operator-assignment: error
   operator-linebreak: error
+  padded-blocks:
+    - error
+    - never
   # These may be a bit controversial, we can try them out and enable them later
   # prefer-const: error
   # prefer-destructuring: error
@@ -226,4 +234,4 @@ globals:
   print: readonly
   printerr: readonly
 parserOptions:
-  ecmaVersion: 2019
+  ecmaVersion: 2020