Include style in Action JSON dictionary

SlackKit/Sources/Action.swift

@@ -54,6 +54,7 @@ public struct Action {
         dict["text"] = text
         dict["type"] = type
         dict["value"] = value
+        dict["style"] = style?.rawValue
         dict["confirm"] = confirm?.dictionary()
         return dict
     }

SlackKit/Sources/SlackKit.swift

@@ -35,7 +35,9 @@ public final class SlackKit: OAuthDelegate {
     public init(withAPIToken token: String, clientOptions: ClientOptions = ClientOptions()) {
         self.clientOptions = clientOptions
         let client = Client(apiToken: token)
-        self.onClientInitalization?(client)
+        DispatchQueue.main.async(execute: {
+            self.onClientInitalization?(client)
+        })
         clients[token] = client
         client.connect(options: self.clientOptions)
     }