Fix typings path

[alevkon]

Due to wrong types path in the package.json, we could not properly import the component.
After merging this PR, we'll be able to import it like that:

import { ReactNativeZoomableView } from '@dudigital/react-native-zoomable-view';

instead of

import ReactNativeZoomableView from '@dudigital/react-native-zoomable-view/src/ReactNativeZoomableView';