add "types" to package.json "exports" (#392)

<img width="821" alt="Screenshot 2024-02-23 at 20 28 42"
src="https://github.com/projectwallace/css-analyzer/assets/1536852/121d6202-6560-496e-824b-8b1fd8ec1c7b">

package.json

@@ -19,7 +19,8 @@
   "unpkg": "./dist/analyzer.umd.js",
   "exports": {
     "require": "./dist/analyzer.cjs",
-    "default": "./dist/analyzer.modern.js"
+    "default": "./dist/analyzer.modern.js",
+    "types": "./dist/index.d.ts"
   },
   "types": "./dist/index.d.ts",
   "engines": {