fix(types): correct a local/import type declaration conflict (#79)

* Fix local/import type declaration conflict

Fixes an error introduced by a backwards incompatible change in
TypeScript 3.7 which fails if you declare a local type with the same
name as an imported type:
https://devblogs.microsoft.com/typescript/announcing-typescript-3-7/#local-and-imported-type-declarations-now-conflict

* Fix typings: only include getProp/parentNode in NativeTestInstance

Author: aiham

typings/query-helpers.d.ts

@@ -8,13 +8,13 @@ export type SelectorMatcherOptions = Omit<MatcherOptions, 'selector'> & {
   selector?: string;
 };
 
-type ReactTestInstance = {
+type ReactTestInstanceExtended = ReactTestInstance & {
   getProp: (name: string) => NativeTestInstance;
   parentNode: NativeTestInstance;
 };
 
 export type NativeTestInstance = Omit<
-  ReactTestInstance,
+  ReactTestInstanceExtended,
   'findAllByProps' | 'findAllByType' | 'findByProps' | 'findByType' | 'instance'
 >;