updated lib to require RN 0.57 minimum

updated testApp to latest RN
updated Fetch to version 3.0.3

metro.config.js

@@ -0,0 +1,17 @@
+/**
+ * Metro configuration for React Native
+ * https://github.com/facebook/react-native
+ *
+ * @format
+ */
+
+module.exports = {
+  transformer: {
+    getTransformOptions: async () => ({
+      transform: {
+        experimentalImportSupport: false,
+        inlineRequires: false,
+      },
+    }),
+  },
+};