fix package.json types entry (#163)

When I installed the package the typescript definition ended up in:

node_modules/@intercom/intercom-react-native/lib/typescript/src/index.d.ts

Co-authored-by: Alexander Trousevich <me@trousev.pro>

Author: ottob

package.json

@@ -4,7 +4,7 @@
   "description": "React Native wrapper to bridge our iOS and Android SDK",
   "main": "lib/commonjs/index",
   "module": "lib/module/index",
-  "types": "lib/typescript/index.d.ts",
+  "types": "lib/typescript/src/index.d.ts",
   "react-native": "src/index",
   "source": "src/index",
   "files": [