Update README.md for 0.1.0 release (#126)

Summary:
Please read through our [contribution guide](https://github.com/pytorch/torchsnapshot/blob/main/CONTRIBUTING.md) prior to creating your pull request.
<!-- Change Summary -->

Pull Request resolved: #126

Test Plan: Fixes #{issue number}

Reviewed By: ananthsub

Differential Revision: D40818661

Pulled By: edward-io

fbshipit-source-id: b1a3590530b587abc5c52dc2e9a14d5095ded6df

Author: edward-io

README.md

@@ -1,4 +1,4 @@
-# torchsnapshot
+# TorchSnapshot (Beta Release)
 
 <p align="center">
 <a href="https://github.com/pytorch/torchsnapshot/actions?query=branch%3Amain"><img src="https://img.shields.io/github/workflow/status/pytorch/torchsnapshot/Unit%20tests/main" alt="build status"></a>
@@ -8,8 +8,6 @@
 <a href="https://github.com/pytorch/torchsnapshot/blob/main/LICENSE"><img src="https://img.shields.io/pypi/l/torchsnapshot" alt="bsd license"></a>
 </div>
 
-**This library is currently in Alpha and currently does not have a stable release. The API may change and may not be backward compatible. If you have suggestions for improvements, please open a GitHub issue. We'd love to hear your feedback.**
-
 A performant, memory-efficient checkpointing library for PyTorch applications, designed with large, complex distributed workloads in mind.
 
 
@@ -20,9 +18,14 @@ Requires Python >= 3.7 and PyTorch >= 1.12
 From pip:
 
 ```bash
+# Stable
+pip install torchsnapshot
+
+# Nightly
 pip install --pre torchsnapshot-nightly
 ```
 
+
 From source:
 
 ```bash