[Build] Update version of setuptools used to generate core package

[tmm1]

This updates setuptools version used in the build pipeline to v75.8.0, which includes pypa/setuptools@f285d01 and generates Metadata: 2.2 manifests for pypi

With this change, it becomes easier to manage flash-attn installation with uv. See astral-sh/uv#6607 (comment)

for some reason, uv always tries to build flash-attn during sync, even though it was not requested

This is expected and required. flash-attn ships as a source distribution, and only at Metadata-Version: 2.1, so you must ask the build backend for its dependencies per the spec -- which in turn requires that its build dependencies are already installed. There's really nothing we can do about this -- it's a problem with the package. They need to upgrade to Metadata-Version: 2.2.

For more details on the current workarounds, see the uv docs which feature a whole section on how to deal with issues trying to install flash-attn.

cc @tridao @charliermarsh

[charliermarsh]

Personally I would use >= here but this is also reasonable.