Update README.md to include diagram (#1319)

Co-authored-by: Sebastian Raschka <[email protected]>

README.md

@@ -29,6 +29,8 @@ Uses the latest state-of-the-art techniques:
 
 </div>
 
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+<img src="https://pl-bolts-doc-images.s3.us-east-2.amazonaws.com/GithubLitGPTDAG2.png" alt="LitGPT steps" width="auto"/>
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 # Finetune, pretrain and deploy LLMs Lightning fast ⚡⚡   
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 # Choose from 20+ LLMs
 LitGPT has 🤯 **custom, from-scratch implementations** of [20+ LLMs](tutorials/download_model_weights.md) without layers of abstraction:   
 
@@ -57,6 +61,7 @@ LitGPT has 🤯 **custom, from-scratch implementations** of [20+ LLMs](tutorials
 
 <details>
   <summary>See full list of 20+ LLMs</summary>
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 #### All models
@@ -88,6 +93,8 @@ LitGPT has 🤯 **custom, from-scratch implementations** of [20+ LLMs](tutorials
 
 </details>
 
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 ## Install LitGPT
 
 Install LitGPT with all dependencies (including CLI, quantization, tokenizers for all models, etc.):
@@ -110,10 +117,9 @@ pip install -e '.[all]'
 ```
 </details>
 
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 # Quick start
 After installing LitGPT, select the model and action you want to take on that model (finetune, pretrain, evaluate, deploy, etc...):