build: bump errorprone plugin version from 1.3.0 to 2.0.2

[hellosagar]

Overview

Increase the error-prone plugin version to 2.0.2 because in their release of 1.3.1 they have fixed a few bugs which will reduce the noise in the warnings

Proposed Changes

For this, I've increased the version to 2.0.2 in the project-level build.gradle
classpath 'net.ltgt.gradle:gradle-errorprone-plugin:2.0.2'

[hoisie]

Thanks!