Update AdaptiveCardMaxVersion to 1.5

Based on current documentation and brief testing, schema
version 1.5 appears to now be supported by Teams Incoming Webhook
Connectors.

refs GH-205

adaptivecard/adaptivecard.go

@@ -39,28 +39,9 @@ const (
  // AdaptiveCardMaxVersion represents the highest supported version of the
  // Adaptive Card schema supported in Microsoft Teams messages.
  //
- // Version 1.3 is the highest supported for user-generated cards.
  // https://docs.microsoft.com/en-us/microsoftteams/platform/task-modules-and-cards/cards/cards-reference#support-for-adaptive-cards
  // https://adaptivecards.io/designer
- //
- // Version 1.4 is when Action.Execute was introduced.
- //
- // Per this doc:
- // https://docs.microsoft.com/en-us/microsoftteams/platform/task-modules-and-cards/cards/cards-reference#support-for-adaptive-cards
- //
- // the "Action.Execute" action is supported:
- //
- // "For Adaptive Cards in Incoming Webhooks, all native Adaptive Card
- // schema elements, except Action.Submit, are fully supported. The
- // supported actions are Action.OpenURL, Action.ShowCard,
- // Action.ToggleVisibility, and Action.Execute."
- //
- // Per this doc, Teams MAY support the Action.Execute action:
- //
- // https://docs.microsoft.com/en-us/adaptive-cards/authoring-cards/universal-action-model#schema
- //
- // AdaptiveCardMaxVersion float64 = 1.4
- AdaptiveCardMaxVersion float64 = 1.3
+ AdaptiveCardMaxVersion float64 = 1.5
  AdaptiveCardMinVersion float64 = 1.0
  AdaptiveCardVersionTmpl string = "%0.1f"
 )