Try adding:

composeOptions {
        kotlinCompilerVersion "1.3.61-dev-withExperimentalGoogleExtensions-20200129"
        kotlinCompilerExtensionVersion "0.1.0-dev04"

    }

Specifically, the

kotlinCompilerVersion

part of this is the important one. Let us know if that ends up working for you (either way, success/failure)! I'm legitimately curious, because kapt isn't a path we have tested very thoroughly yet.