[llvm] workflows/release-lit: Update workflow and enable trusted publishing with pypi (PR #174907)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

> I'm also not sure if we should keep the upload to the test server.

It would be nice to have, but not strictly necessary. test PyPI is also a bit annoying right now because I tried requesting an organization account for LLVM over there and it hasn't gotten approved. https://github.com/pypi/warehouse/issues/14972

https://github.com/llvm/llvm-project/pull/174907