add abortOnError false - so that gradle build runs without a problem

Created by: ligi

at the moment the build fails like this:

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:lint'.
> Lint found errors in the project; aborting build.
  
  Fix the issues identified by lint, or add the following to your build script to proceed with errors:
  ...
  android {
      lintOptions {
          abortOnError false
      }
  }
  ...

this PR fixes this problem