Remove the Python 3.15 awswrangler and pyarrow markers once awswrangler allows pyarrow 26 #1180

Use case

#1164 added two temporary dependency markers so that the development lock installs on Python 3.15:

• benchmarks/pyproject.toml:19: "awswrangler>=3.17,<4; python_version < '3.15'"
• pyproject.toml:97 (dev group): "pyarrow>=26.0.0; python_version >= '3.15'"

pyarrow 26.0.0 is the first release with cp315 wheels, but every released awswrangler requires pyarrow<26.0.0 (3.17.1, the latest, as of 2026-10-15).
Because the benchmarks share the workspace lock, the lock otherwise keeps pyarrow 25.0.1 for Python 3.15 as well, and the dev environment cannot install it.
As a result, the benchmark environment cannot be installed on Python 3.15, and pyarrow is locked at different versions for 3.11–3.14 (25.0.1) and 3.15 (26.0.0).

awswrangler raised its cap to pyarrow<27.0.0 and added Python 3.15 support in aws/aws-sdk-pandas#3511 (merged 2026-10-14), which is not released yet.

Proposed change

After an awswrangler release that allows pyarrow 26:

1. Remove the python_version < '3.15' marker from the benchmarks' awswrangler dependency and raise its floor to that release.
2. Remove the dev-group pyarrow>=26.0.0; python_version >= '3.15' line and its comment.
3. Re-lock with a uv version that keeps lock revision 3 (the uv version pinned by the benchmark stack must read it), upgrading awswrangler and pyarrow, and confirm that one pyarrow version with cp315 wheels is locked for every supported Python.

Validation plan (if implementing)

• uv lock --check, uv sync --group dev on Python 3.15, and just lint.
• just benchmark test (Python 3.12), since the benchmarks' awswrangler and pyarrow versions change.
• The Test workflow on every supported Python version, since pyarrow changes for 3.11–3.14.