Link to bug and more complete repro

* Added link to the [bug][1] into Readme
* Added more complete instrumentation, by instrumenting App with an event
  - Would have been unnecessary though I think as default instrumentation seems to already send data
* Commented telemetry.ts on what is the bug (error description)

[1]: microsoft/ApplicationInsights-JS#2336

README.md

@@ -1,6 +1,9 @@
 # Getting Started with Create React App
 
-This project was bootstrapped with [Create React App](https://github.com/facebook/create-react-app).
+This is a repro for [github issue 2336 in *microsoft/ApplicationInsights-JS* repo](https://github.com/microsoft/ApplicationInsights-JS/issues/2336).
+
+Just run `npm run build` to get the build error on `ignoreHeaders`.
+
 
 ## Available Scripts
 

src/App.tsx

@@ -1,8 +1,20 @@
-import React from 'react';
+import React, { useEffect } from 'react';
 import logo from './logo.svg';
 import './App.css';
+import {appInsights} from './telemetry';
+import { useAppInsightsContext } from '@microsoft/applicationinsights-react-js';
 
 function App() {
+  // const appInsights = useAppInsightsContext();
+
+  useEffect(() => {
+    if (appInsights) {
+      console.log("AppLoaded");
+      appInsights.trackEvent({ name: "AppLoaded" });
+      alert("AppLoaded");
+    }
+  }, [appInsights]);
+
   return (
     <div className="App">
       <header className="App-header">

src/telemetry.ts

@@ -15,6 +15,8 @@ const appInsights = new ApplicationInsights({
     disableFetchTracking: false,
     //enableRequestHeaderTracking: true, // Enable to get request headers in dependency logs
     enableResponseHeaderTracking: true, // Enable to get response headers in dependency logs
+    // BUG: FOLLOWING LINE GIVES ERROR ON BUILD
+    // Object literal may only specify known properties, and 'ignoreHeaders' does not exist in type 'IConfiguration & IConfig'.ts(2353)
     ignoreHeaders: [
       "Authorization",
       "X-API-Key",