refactor: introduce WebhookAPIError as an extension of native Error

src/WebhookAPI/WebhookAPIError.ts

@@ -0,0 +1,15 @@
+/**
+ * WhatsApp NodeJS SDK.
+ *
+ * @since  2.0.0
+ * @author Great Detail Ltd <[email protected]>
+ * @author Dom Webber <[email protected]>
+ * @see    https://greatdetail.com
+ */
+
+export default class WebhookAPIError extends Error {
+  constructor(message: string) {
+    super(message);
+    this.name = "WebhookAPIError";
+  }
+}