Fix ESRP rejection by upgrading setuptools for PEP 625 sdist naming

[andystaples]

Problem

The ESRP release failed with:

Filename 'azure-functions-durable-1.6.0.tar.gz' is invalid, should be 'azure_functions_durable-1.6.0.tar.gz'.

The sdist was produced with a legacy hyphenated filename, but ESRP/PyPI now enforce the PEP 625 normalized form (dashes -> underscores).

Root cause

The build steps never install or upgrade setuptools, so the build uses whatever ships with the Python 3.10 venv created by UsePythonVersion@0 -- setuptools 65.5.0. PEP 625 sdist-name normalization only became the default in setuptools 69.3.0, so the older bundled version emits azure-functions-durable-*.tar.gz.

Fix

Install setuptools>=69.3.0 (alongside wheel) before building, in both eng/templates/build.yml (official/ESRP path) and azure-pipelines.yml (CI).

Verification

Simulated the exact build (python setup.py sdist bdist_wheel) in clean Python 3.10 venvs:

setuptools	sdist filename	Result
65.5.0 (bundled today)	azure-functions-durable-*.tar.gz	rejected
69.2.0	azure-functions-durable-*.tar.gz	hyphen
69.3.0 (chosen lower bound)	azure_functions_durable-*.tar.gz	underscore
83.0.0 (latest)	azure_functions_durable-*.tar.gz	underscore

The wheel was already correctly named even with old setuptools; only the sdist was affected, so this is the only change required.