feat: export types (#31)

---------

Co-authored-by: legobeat <109787230+legobeat@users.noreply.github.com>
Co-authored-by: legobt <6wbvkn0j@anonaddy.me>

Author: abretonc7s

CHANGELOG.md

@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- Export TypeScript types ([#31](https://github.com/MetaMask/object-multiplex/pull/31))
 
 ## [1.2.0]
 ### Changed

package.json

@@ -3,6 +3,7 @@
   "version": "1.2.0",
   "description": "Simple stream multiplexing for objectMode.",
   "main": "dist/index.js",
+  "types": "dist/index.d.ts",
   "repository": {
     "type": "git",
     "url": "https://github.com/MetaMask/object-multiplex.git"