build: bump stable-fast-pruna requirement

[gsprochette]

Description

This PR bumps the requirement on stable-fast-pruna from 1.0.7 to 1.0.8 which is built on torch 2.9 and cuda 12.8.
This implicitely pins the stable-fast extra to torch==2.9, builds requiring other versions should use the extra-index-url.

Related Issue

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Additional Notes

[begumcig]

Let's gooooo