Fix exports field in package.json (#351)

* Fix exports field in `package.json`

* Use exports syntax for both new and old versions of Node

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Co-authored-by: Mark Amery <markrobertamery@gmail.com>

Author: fisker

package.json

@@ -37,7 +37,8 @@
       "require": "./lib/index.js"
     },
     "./package.json": "./package.json",
-    "./": "./"
+    "./": "./",
+    "./*": "./*"
   },
   "scripts": {
     "clean": "rm -rf lib/ dist/",