Fully define dependencies for async support via optional dependency group

The current docs suggest adding aiohttp as a dependency to create an async app, but this creates a direct dependency on aiohttp for consumers of slack-bolt on what is is really a transitive dependency for the consumer of slack-bolt. This is especially important because this leaves it to consumers to find compatible versions of slack-bolt and aiohttp without the aide of a package manager.

slack-bolt should define an optional dependency group and include aiohttp so that consumers of this library don't need to maintain a dependency on a transitive. Consumers would be able to uv add slack-bolt[async] for example to include the optional dependencies.

Category (place an x in each of the [ ])

• slack_bolt.App and/or its core components
• slack_bolt.async_app.AsyncApp and/or its core components
• Adapters in slack_bolt.adapter
• [] Others

Requirements

Please read the Contributing guidelines and Code of Conduct before creating this issue or pull request. By submitting, you are agreeing to those rules.

从 slack_bolt.async_app.AsyncApp 的文档以及定义依赖项的包元数据开始。检查当前如何安装 async 支持，然后验证可选的 async 依赖项组包含 aiohttp，并且文档中说明的 uv add slack-bolt[async] 工作流会安装它，而不要求使用者直接管理它。