chore: add "types" conditions for TS "nodenext" resolution (#40)

* fix: TS .d.ts resolution (#1)

There are types at '/node_modules/dset/index.d.ts', but this result could not be resolved when respecting package.json "exports". The 'dset' library may need to update its package.json or typings.ts(7016)

* Update package.json (#2)

* Simplified package exports

* Updated back to original repo

* Update package.json

---------

Co-authored-by: Luke Edwards <luke.edwards05@gmail.com>

package.json

@@ -11,10 +11,12 @@
   "license": "MIT",
   "exports": {
     ".": {
+      "types": "./index.d.ts",
       "import": "./dist/index.mjs",
       "require": "./dist/index.js"
     },
     "./merge": {
+      "types": "./merge/index.d.ts",
       "import": "./merge/index.mjs",
       "require": "./merge/index.js"
     },