python3-setuptools: upgrade 50.3.2 -> 51.0.0

No upstream release notes.

Upstream commits since 50.3.2:

b6bbe236 Bump version: 50.3.2 → 51.0.0
7f477c52 Merge pull request #2472 from pypa/bugfix/2471-remove-deps
2a0463cb Update changelog.
99bc2c11 Remove tests guaranteeing that (vendored) dependencies can be installed without setuptools.
65441834 Remove conditional skip, no longer relevant.
9365c7ed Merge pull request #2468 from wimglenn/patch-1
43b0b81e Merge pull request #2461 from webknjaz/testing/gha-fix-set-env-usage
43f76003 Merge pull request #2460 from HaraldKorneliussen/master
2065f85d Merge pull request #2444 from zegor/patch-1
e9617599 Merge pull request #2439 from mgedmin/patch-1
475fb309 Update docs/pkg_resources.rst
b4de397a fix broken link to entry-points details
4a4d50af Fix all deprecated set-env and add-path uses @ GHA
b20d12e1 Fixes syntax issues in quickstart (#2448)
5cf3865f Merge pull request #2457 from webknjaz/testing/gha-broken-setup-python
de48cfdb Temporarily allow `set-env` GHA commands
ec944a40 Upgrade GHA actions using deprecated env mechanism
d7170a28 Update quickstart.rst
0e1fc1c6 s/517/PEP 517/
544687c3 Merge pull request #2437 from pypa/feature/rtd-2
3ca9e461 Merge pull request #2436 from webknjaz/maintenance/changelog-reconstruction
8ad16115 Merge pull request #2435 from pypa/debt/drop-py35
6597dcb6 Switch to RTD v2 config
7cf674e1 Reconstruct changelog with categories from history
97ee6624 Remove Python 3.5 from Appveyor tests
3dd7313d Bump PPC runs
d490709b Merge pull request #2431 from webknjaz/bugfixes/pr-template-docs-links
66ca4205 Use 'virtualenv.python'. Fixes #2434.
419087c4 Merge branch 'master' into debt/drop-py35
38de858e Update changelog
6d33d5dd 📝 Update devguide links in the PR template
898ae046 Merge pull request #2430 from webknjaz/bugfixes/sphinx-failures
a94c2c3d 📝 Add change notes
e711cb07 🐛📝 Fix "Title level inconsistent" in changelog
9ab7bc54 Clean up syntax on entry_points.console_scripts. Fixes #2429.
2ff24f67 🐛📝

 Fix the TOC link to the relocated dev guide
a5dbf964 Drop support for Python 3.5.

Signed-off-by: Tim Orling <timothy.t.orling@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>