feat: swap action (#657)

leaves-api/src/main/java/org/leavesmc/leaves/entity/bot/action/SwapAction.java

@@ -0,0 +1,11 @@
+package org.leavesmc.leaves.entity.bot.action;
+
+import org.bukkit.Bukkit;
+/**
+ * Represents an action for a bot to swap items between the main hand and off-hand.
+ */
+public interface SwapAction extends BotAction<SwapAction> {
+    static SwapAction create() {
+        return Bukkit.getBotManager().newAction(SwapAction.class);
+    }
+}