fix(npm): add "types" entry to package.json

This fixes the ts error "error TS7016: Could not find a declaration file for module
'react-to-typescript-definitions'".

Author: unstubbable

Diff for: package.json

@@ -3,6 +3,7 @@
   "version": "0.24.0",
   "description": "Create typescript definitions files (d.ts) from react components",
   "main": "dist/src/index.js",
+  "types": "dist/src/index.d.ts",
   "bin": {
     "react2dts": "cli.js"
   },