remove alpha status (#225)

Summary:
the project is now ready to use so remove the warning about it being in alpha

Author: tushar00jain

README.md

@@ -21,11 +21,6 @@ Easy Per Step Fault Tolerance for PyTorch
 
 ---
 
-> ⚠️ WARNING: This is an alpha prototype for PyTorch fault tolerance and may have bugs
-> or breaking changes as this is actively under development. We'd love to collaborate
-> and contributions are welcome. Please reach out if you're interested in torchft
-> or want to discuss fault tolerance in PyTorch
-
 This repository implements techniques for doing a per-step fault tolerance so
 you can keep training if errors occur without interrupting the entire training
 job.