fix: do not bundle react with es5 build, use it as external peer dependency instead

Author: solkimicreb

__mocks__/react-easy-state.js

@@ -1 +1,5 @@
+// use this to test the es6 modules build
 export * from '../src'
+
+// use to test the commonJS build
+// export * from '../dist/easyState'