Error: Problem validating fields in app.json. See https://docs.expo.io/workflow/configuration/ • should NOT have additional property 'config'

I'm using ReactNative Expo for developing android/iOS app also added AdMOB. Issue is when I run expo build:ios, it's returning following error Problem validating fields in app.json. See https://docs.expo.io/workflow/configuration/• should NOT have additional property 'config'.

Here is my app.json file:

{"expo": {"name": "AppName","slug": "AppSlug","version": "1.0.0","orientation": "portrait","icon": "./assets/icon.png","splash": {"image": "./assets/splash.png","resizeMode": "contain","backgroundColor": "#ffffff"    },"updates": {"fallbackToCacheTimeout": 0    },"assetBundlePatterns": ["**/*"    ],"ios": {"supportsTablet": true    },"config": {"googleMobileAdsAppId": "ca-app-pub-xxxxxx"    },"android": {"package": "com.x.yyyyy","config": {"googleMobileAdsAppId": "ca-app-pub-xxxxxx"      }    }  }}