Updated to version 0.4.0 with new features

- Enhanced error handling in async crawler.
  - Added flexible options in Markdown generation.
  - Updated user agent settings for improved reliability.
  - Reflected changes in documentation and examples.

crawl4ai/user_agent_generator.py

@@ -236,6 +236,7 @@ class UserAgentGenerator:
 # Example usage:
 if __name__ == "__main__":
     generator = UserAgentGenerator()
+    print(generator.generate())
     
     print("\nSingle browser (Chrome):")
     print(generator.generate(num_browsers=1, browser_type='chrome'))