Add missing complex-types.d.ts to package.json

Related-to: GH-4.
Closes Gh-5.

Reviewed-by: Titus Wormer <[email protected]>

Author: JuanM04

package.json

@@ -31,6 +31,7 @@
   "main": "index.js",
   "types": "index.d.ts",
   "files": [
+    "complex-types.d.ts",
     "index.d.ts",
     "index.js"
   ],