Update pyre-check.org/play to use Python 3.11

[hauntsaninja]

It looks like it currently targets 3.10. Targeting 3.11 (or 3.12) makes use of assert_type just a tiny bit easier. The new conformance tests in https://github.com/python/typing make heavy use of this. Alternatively, allow specifying the target Python version in the playground.

[stroxler]

Hmm. I can look into bumping the version (multi-version is probably trickier the way we currently have it set up)

That said, I don't think we actually support assert_type right now, so maybe there should be an issue for that too; I'm hoping we can start looking at getting conformance checks running on Pyre, but there's work probably needed to even start on that.

[stroxler]

The playground is now running on 3.12, but I'm going to leave this issue open because the current release of open-source Pyre still doesn't support assert_type.

I've fixed this on trunk (diffs finished landing today) but I need to do an open source release and a redeploy before it will show up in the playground.