Update vendor (#1384)

vendor/github.com/slack-go/slack/socket_mode.go

@@ -0,0 +1,34 @@
+package slack
+
+import (
+	"context"
+)
+
+// SocketModeConnection contains various details about the SocketMode connection.
+// It is returned by an "apps.connections.open" API call.
+type SocketModeConnection struct {
+	URL  string                 `json:"url,omitempty"`
+	Data map[string]interface{} `json:"-"`
+}
+
+type openResponseFull struct {
+	SlackResponse
+	SocketModeConnection
+}
+
+// StartSocketModeContext calls the "apps.connections.open" endpoint and returns the provided URL and the full Info block with a custom context.
+//
+// To have a fully managed Socket Mode connection, use `socketmode.New()`, and call `Run()` on it.
+func (api *Client) StartSocketModeContext(ctx context.Context) (info *SocketModeConnection, websocketURL string, err error) {
+	response := &openResponseFull{}
+	err = postJSON(ctx, api.httpclient, api.endpoint+"apps.connections.open", api.appLevelToken, nil, response, api)
+	if err != nil {
+		return nil, "", err
+	}
+
+	if response.Err() == nil {
+		api.Debugln("Using URL:", response.SocketModeConnection.URL)
+	}
+
+	return &response.SocketModeConnection, response.SocketModeConnection.URL, response.Err()
+}