How to change the proguard mapping file name in gradle for Android project

Simpler solution.

applicationVariants.all { variant ->
        if (variant.getBuildType().isMinifyEnabled()) {
            variant.assemble.doLast {
                copy {
                    from variant.mappingFile
                    into "${rootDir}/proguardTools"
                    rename { String fileName ->
                        "mapping-${variant.name}.txt"
                    }
                }
            }
        }
    }