[Usability] Does README need to be updated to switch to alpha?

[orionr]

We still have the following section, but could we switch that to saying that this can be used in production (like we do at Meta) or remove this all together?

Important: This is a preview release

This is a preview version of ExecuTorch and should be used for testing and evaluation purposes only. It is not recommended for use in production settings. We welcome any feedback, suggestions, and bug reports from the community to help us improve the technology. Please use the PyTorch Forums for discussion and feedback about ExecuTorch using the ExecuTorch category, and our GitHub repository for bug reporting.

The ExecuTorch code and APIs are still changing quickly, and there are not yet any guarantees about forward/backward source compatibility. We recommend using the latest v#.#.# release tag from the Releases page when experimenting with this preview release.

cc @byjlw @dbort

[byjlw]

I say we target removing this by EOM. Would like to feel good about the stability before we remove