v0.26.0

Kotlin

• Upgrade kotlinx.serialization now that KAML supports it. (#1018)
• Makes BackStackContainer.update protected, required for customization. (#1088)

Swift

• Vend preferredContentSize through the DescribedViewController (#1051)
• Add ContainerViewController init with AnyWorkflowConvertable (#1092)
• Provide empty makeInitialState and workflowDidChange when State is Void (#1094)