message: Make redirectUri optional in type definition
  The `redirectUri` property of `SlackAdapterOptions` is only relevant for apps that uses OAuth. It is treated as optional by the code and the type definitions should reflect that.
diff: @@ -729,7 +729,7 @@ export interface SlackAdapterOptions {
  /**
  * The URL users will be redirected to after an oauth flow. In most cases, should be `https://<mydomain.com>/install/auth`
  */
  - redirectUri: string;
  + redirectUri?: string;
  /**
  * A method that receives a Slack team id and returns the bot token associated with that team. Required for multi-team apps.
  