[meta] add funding field

Author: ljharb

package.json

@@ -52,6 +52,9 @@
     "email": "[email protected]",
     "url": "http://substack.net"
   },
+  "funding": {
+    "url": "https://github.com/sponsors/ljharb"
+  },
   "license": "MIT",
   "browser": {
     "./util.inspect.js": false