4.0.0-alpha.15

Major Changes

• [plugins] plugins support for graphql clients using kotlinx serialization (#1070) @dariuszkuc
• [plugin] update client generator to support kotlinx serialization (#1069) @dariuszkuc
• [client] create new GraphQL client serialization abstraction (#1066) @dariuszkuc
• Add support for federated tracing (#1065) @smyrick

Non-version Changes

• Incorrect Gradle Target for Executing/Building the Example Spring Server (#1063) @acidbluebriggs
• Delete versioned 4.x.x docs for renamed current docs (#1060) @smyrick
• fix release-docs workflow (#1061) @dariuszkuc