I got the android app working.
Android is adding the dependency com.squareup.okhttp3:okhttp which is set to 3.+
Now it picks up the latest version of this library which is 3.11 (pushed July 11th)
This was causing the app crash.
Getting to this point took considerable amount of time and investigation as cordova internally pulls up this dependency and is not specified in the ionic package.json.
Solution to this problem:
We need to manually update project.properties in platforms/android with the below entry:
cordova.system.library.5=com.squareup.okhttp3:okhttp:3.10.0
Run ionic cordova build android