Update README with Chipper model announcement (#155)

Update README with Chipper model beta version announcement.

Author: ron-unstructured

README.md

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 <h3 align="center">
   <img src="img/unstructured_logo.png" height="200">
 </h3>
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 <h3 align="center">
   <p>API Announcement!</p>
 </h3>
 
-<p>While access to the hosted Unstructured API will remain free, API Keys will soon be required to make requests. To prevent any disruption, get yours <a href="https://www.unstructured.io/api-key/">here</a> now and start using it today!</p>
-  
-<p>Checkout the rest of the readme below to get started making API calls. 
-We'd love to hear your feedback, let us know how it goes in our
-  <a href="https://join.slack.com/t/unstructuredw-kbe4326/shared_invite/zt-1x7cgo0pg-PTptXWylzPQF9xZolzCnwQ"> community slack</a>. And stay tuned for improvements to both quality and performance!</p>
+We are thrilled to announce our newly launched [Unstructured API](https://unstructured-io.github.io/unstructured/api.html). While access to the hosted Unstructured API will remain free, API Keys will soon be required to make requests. To prevent disruption, get yours [here](https://www.unstructured.io/api-key/) now and start using it today! Check out the [readme](https://github.com/Unstructured-IO/unstructured-api#--) here to get started making API calls.</p>
+
+#### :rocket: Beta Feature: Chipper Model
+
+We are releasing the beta version of our Chipper model to deliver superior performance when processing high-resolution, complex documents. To start using the Chipper model in your API request, you can utilize the `hi_res` strategy. Please refer to the documentation [here](https://unstructured-io.github.io/unstructured/api.html#strategies).
+
+As the Chipper model is in beta version, we welcome feedback and suggestions. For those interested in testing the Chipper model, we encourage you to connect with us on [Slack community](https://join.slack.com/t/unstructuredw-kbe4326/shared_invite/zt-1x7cgo0pg-PTptXWylzPQF9xZolzCnwQ).
 
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