cibuildwheel: remove useless pp* skip selector

[Polandia94]

What do these changes do?

Removes the dead pp* cibuildwheel skip selector. PyPy build groups have not been enabled by default since cibuildwheel 3.0, so the selector matches nothing and cibuildwheel only warns:

Invalid skip selector: 'pp*'. This selector matches a group that wasn't enabled.

Mirrors aio-libs/multidict#1283, removing it from both pyproject.toml and the two wheel-tags-to-skip call sites in .github/workflows/ci-cd.yml (each branch had pp* appended, which fed into CIBW_SKIP regardless of the pyproject.toml setting).

Are there changes in behavior for the user?

No. Only the wheel build pipeline configuration changes, not the published wheels.

Related issue number

Related to aio-libs/multidict#1283 (does not close it).

Checklist

• I think the code is well written
• Unit tests for the changes exist (N/A, CI-only configuration change)
• Documentation reflects the changes (N/A)
• Add a new news fragment into the CHANGES/ folder

Agent run details (optional, for reviewers)

Verified: grepped the full working tree for pp* after the change (no matches left), and confirmed pyproject.toml (tomllib) and .github/workflows/ci-cd.yml (PyYAML) still parse. Did not run the full test suite or docs spellcheck in the environment this was drafted in, since network access there is restricted; please confirm CI is green before marking ready.

Drafted with Claude (Sonnet 5) in a Cowork session. Reviewed by @Polandia94

[codspeed-hq]

Merging this PR will not alter performance

✅ 4 untouched benchmarks

---

_{Comparing Polandia94:remove-cibuildwheel-pp-skip (cd82004) with master (61949ea)}

[greptile-apps]

Confidence Score: 5/5

No blocking failure remains.

No accepted blocking findings remain.

T-Rex Logs

What T-Rex did

• Ran the cibuildwheel selector validation harness before and after the change, invoking uv run with cibuildwheel==4.2.0 against base and HEAD snapshots, and exercised the CIBW_SKIP selector across values.
• Validated that the identifier/configuration validation completed and that full wheel builds were intentionally out of scope for this check.

_{Ran code and verified through T-Rex}

_{Reviews (5): Last reviewed commit: "Merge branch 'master' into remove-cibuil..." | Re-trigger Greptile}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (61949ea) to head (cd82004).

Additional details and impacted files

@@            Coverage Diff            @@
##            master      #291   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           10        10           
  Lines          437       437           
  Branches        17        17           
=========================================
  Hits           437       437           

Flag	Coverage Δ
CI-GHA	97.94% <ø> (ø)
OS-Linux	97.94% <ø> (ø)
OS-Windows	94.96% <ø> (ø)
OS-macOS	94.96% <ø> (ø)
Py-3.10	94.96% <ø> (ø)
Py-3.11	96.56% <ø> (ø)
Py-3.12	96.56% <ø> (ø)
Py-3.13	96.56% <ø> (ø)
Py-3.14	96.54% <ø> (ø)
Py-3.14t	96.54% <ø> (ø)
Py-pypy-3.10	78.48% <ø> (ø)
VM-macos-latest	94.96% <ø> (ø)
VM-ubuntu-latest	97.94% <ø> (ø)
VM-windows-11-arm	94.73% <ø> (ø)
VM-windows-latest	94.96% <ø> (ø)
pytest	97.94% <ø> (ø)

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[webknjaz]

Drafted with Claude (Sonnet 5) in a Cowork session. Reviewed by @Polandia94

FTR, in the age of ai slop, such comments make PRs look suspicious because various inauthentic mass-contribs add such statements to their templates automatically, and then you open the diff tab and there's something like "100500 lines removed, 1 line saying hello world added" 🫠

Not sure how we can deal with these better though.. Just watch out for the claims that your agent makes for you.