When building for first time, jackOptions method not found

[luongthomas]

I cloned this repo and started building it for the first time which resulted in an error of not being able to find the method jackOptions.

I found a similar StackOverflow post and removed the jackOptions in the gradle files.

https://stackoverflow.com/questions/38944593/android-studio-error-when-add-java8-support

Afterwards it was able to build correctly.

Is it okay if I create a PR to fix this?