Correct propery 'types' in package.json

[technobuddha]

The correct property name for type definitions in package.json is "types" not "typings".

Without this change, you can not import from react2angular in typescript.

[RusmiselE-lattice]

Non-issue. From typescript docs: 'Note that the "typings" field is synonymous with "types", and could be used as well.' https://www.typescriptlang.org/docs/handbook/declaration-files/publishing.html#including-declarations-in-your-npm-package