Improve generated code compiler arg
The default README only described how to disable errorprone warnings in non-test code.
@@ -225,7 +225,7 @@ dependencies {
Tip: Warnings on generated code can be suppressed as follows:
```groovy
-compileJava {
+tasks.withType(JavaCompile) {
options.compilerArgs += ['-XepDisableWarningsInGeneratedCode']
}
```
