prow/cmd/build/controller.go
func injectEnvironment(b *buildv1alpha1.Build, rawEnv map[string]string) {
	for i := range b.Spec.Steps { // Inject environment variables to each step
		defaultEnv(&b.Spec.Steps[i], rawEnv)
	}
	if b.Spec.Template != nil { // Also add it as template arguments
		defaultArguments(b.Spec.Template, rawEnv)
	}
}
func injectEnvironment(b *buildv1alpha1.Build, rawEnv map[string]string) {
	for i := range b.Spec.Steps { // Inject environment variables to each step
		defaultEnv(&b.Spec.Steps[i], rawEnv)
	}
	if b.Spec.Template != nil { // Also add it as template arguments
		defaultArguments(b.Spec.Template, rawEnv)
	}
}
// injectEnvironment will add rawEnv to the build steps and/or template arguments.