Add the applied_tags field to ExecuteWebhook (#3437)

Allows webhooks to create forum threads with tags applied to them.

Author: smolestcookie

src/builder/execute_webhook.rs

@@ -75,6 +75,8 @@ pub struct ExecuteWebhook {
     flags: Option<MessageFlags>,
     #[serde(skip_serializing_if = "Option::is_none")]
     thread_name: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    applied_tags: Option<Vec<ForumTagId>>,
     attachments: EditAttachments,
 
     #[serde(skip)]
@@ -343,6 +345,12 @@ impl ExecuteWebhook {
         self
     }
 
+    /// Tags for thread being created (requires the webhook channel to be a forum channel)
+    pub fn applied_tags(mut self, applied_tags: Vec<ForumTagId>) -> Self {
+        self.applied_tags = Some(applied_tags);
+        self
+    }
+
     /// Allows sending non interactive components on non application owned webhooks.
     pub fn with_components(mut self, with_components: bool) -> Self {
         self.with_components = Some(with_components);