fix(store): add DefaultProjectorFn to public API (#2090)

Allows you to fully type the selector without reaching into the src folder

Author: brandonroberts

modules/store/src/index.ts

@@ -33,6 +33,7 @@ export {
   MemoizedSelector,
   MemoizedSelectorWithProps,
   resultMemoize,
+  DefaultProjectorFn,
 } from './selector';
 export { State, StateObservable, reduceState } from './state';
 export {