Errors Running demo & Documentation

[HansUXdev]

Thanks for putting together this demo. However, I'm running into issues I don't see documented.
The instructions provided are:

### iOS ([example setup](https://github.com/Cierpliwy/SensorTag))

1. `npm install --save react-native-ble-plx`
2. `npx react-native link react-native-ble-plx`
3. Open Xcode workspace located inside `ios` folder and add empty Swift file if you don't have at least one:
   - Select File/New/File...
   - Choose Swift file and click Next.
   - Name it however you want, select your application target and create it.
   - Accept to create Objective-C bridging header.
4. Update your `ios/Podfile` to contain (it may be already there):
     pod 'react-native-ble-plx', :path => '../node_modules/react-native-ble-plx'
5. Enter `ios` folder and run `pod update`
6. Add `NSBluetoothAlwaysUsageDescription` in `info.plist` file. (it is a requirement since iOS 13)
7. If you want to support background mode:
   - In your application target go to `Capabilities` tab and enable `Uses Bluetooth LE Accessories` in
     `Background Modes` section.
   - Pass `restoreStateIdentifier` and `restoreStateFunction` to `BleManager` constructor.

Errors

1. error React Native CLI uses autolinking for native dependencies, but the following modules are linked manually:
2. error Failed to build iOS project. We ran "xcodebuild" command but it exited with error code 65. To debug build logs further, consider building your app with Xcode.app, by opening SensorTag.xcworkspace.
3. error: /NativeApps/BLE-SensorTag/ios/Pods/Target Support Files/Pods-SensorTag/Pods-SensorTag.debug.xcconfig: unable to open file (in target "SensorTag" in project "SensorTag") (in target 'SensorTag')
4. 2021-01-20 08:23:42.176 xcodebuild[33027:16762118] DTDeviceKit: deviceType from ae61ebde7770c6eaf1d74b7b9c15171289c87abd was NULL
5. 2021-01-20 08:23:42.504 xcodebuild[33027:16762551] DTDeviceKit: deviceType from ae61ebde7770c6eaf1d74b7b9c15171289c87abd was NULL
6. 2021-01-20 08:23:42.980 xcodebuild[33027:16762553] iPhoneConnect: 📱<DVTiOSDevice (0x7f92ddb7d830), Brett’s iPhone, iPhone, 14.2 (18B92), ae61ebde7770c6eaf1d74b7b9c15171289c87abd> unable to mount developer disk image, (Error Domain=com.apple.dtdevicekit Code=601 "Could not locate device support files." UserInfo={DeviceType=iPhone10,4, NSLocalizedDescription=Could not locate device support files., NSLocalizedRecoverySuggestion=This iPhone 8 (Model A1863, A1905, A1906, A1907) is running iOS 14.2 (18B92), which may not be supported by this version of Xcode.}) {
   DeviceType = "iPhone10,4";
   NSLocalizedDescription = "Could not locate device support files.";
   NSLocalizedRecoverySuggestion = "This iPhone 8 (Model A1863, A1905, A1906, A1907) is running iOS 14.2 (18B92), which may not be supported by this version of Xcode.";
   }
   ** BUILD FAILED **

What I've done

1. downloaded the repo and ran npm i, ran npm run ios, which errored out.
2. for issue 1, I tried unlinking and linking the native dependencies then re-ran the command
3. Tried fixing issue 2-6 by updating xcode related issues