Issue/8 flavor support

[yshrsmz]

close #8

• README
• Test

final API:

buildkonfig {
  packageName = "com.example"

  defaultConfigs {
    // this is the default of defaultConfigs
  }
  defaultConfigs("dev") {}
  defaultConfigs("release") {}

  targetConfigs {
    // targetConfigs without flavor acts as a default for each target
  }
  targetConfigs("dev") {
    android {
    }
    ios {
    }
  }
  targetConfigs("release") {
    android {
    }
    // you don't need to configure each target.
    // non-configured target will be fallback to default configs
  }
}

you can specify flavor via property buildkonfig.flavor, like

$ ./gradlew build -Pbuildkonfig.flavor=dev

Or you can provide it via gradle.properties

[benlancaster]

Do you have an example of how to use this with build.gradle.kts?

    targetConfigs("usa") {
        android {
            dependencies {
                implementation(project(":usaGreeter"))
            }
        }
    })

yields:

Type mismatch: inferred type is () -> Unit but Closure<*> was expected

With