Add callback_id to BlockActions, fix block::sections can also only have an accessory

src/Blockkit/Blocks/Elements/Button.php

@@ -9,6 +9,7 @@ final class Button extends Element
 {
 	protected const LIMITS = [
 		'action_id' => 255,
+		'callback_id' => 255,
 		'text' => 75,
 		'url' => 3000,
 		'value' => 2000,
@@ -40,6 +41,13 @@ final class Button extends Element
 
 	/* OPTIONAL ITEMS */
 
+	public function callback_id(string $string): self
+	{
+		$this->callback_id = $string;
+
+		return $this;
+	}
+
 	public function confirm(Confirm $confirm): self
 	{
 		$this->confirm = $confirm;

src/Blockkit/Blocks/Section.php

@@ -43,8 +43,8 @@ final class Section extends Blocks
 
 	public function jsonSerialize()
 	{
-		if (! $this->text && ! $this->fields)
+		if (! $this->text && ! $this->fields && ! $this->accessory)
-			throw new Exception('Must define text or fields');
+			throw new Exception('Must define text, accessory or fields');
 
 		return parent::jsonSerialize();
 	}

src/Interactive/BlockActions.php

@@ -74,7 +74,13 @@ class BlockActions extends Base
 				return object_get($this->_data,$key);
 
 			case 'callback_id':
+				switch (object_get($this->_data,'type')) {
+					case 'block_actions':
+						return object_get(Arr::get(object_get($this->_data,'actions'),$this->index),$key);
+					// @todo Dont assume this is a view
+					default:
 						return object_get($this->_data,'view.callback_id');
+				}
 
 			case 'channel_id':
 				return object_get($this->_data,'channel.id') ?: Channel::findOrFail($this->action('value'))->channel_id;