UPDATE: Fixed broken examples links (microsoft#1886)

* UPDATE: Fixed broken examples links

Fixed the two broken links in the examples page. All other links confirmed to work.

* Update Examples.md

Author: swiecki

website/docs/Examples.md

@@ -98,7 +98,7 @@ Links to notebook examples:
 ### Utilities
 - API Unification  - [View Documentation with Code Example](https://microsoft.github.io/autogen/docs/Use-Cases/enhanced_inference/#api-unification)
 - Utility Functions to Help Managing API configurations effectively - [View Notebook](/docs/topics/llm_configuration)
-- Cost Calculation - [View Notebook](https://github.com/microsoft/autogen/blob/main/notebook/oai_client_cost.ipynb)
+- Cost Calculation - [View Notebook](https://github.com/microsoft/autogen/blob/main/notebook/agentchat_cost_token_tracking.ipynb)
 
 ### Inference Hyperparameters Tuning