fix: bump requests-cache dependency

[timothykou]

Summary

• Bump requests-cache from 1.2.0 to 1.3.2
• Keeps the existing exact-pin dependency style used in pyproject.toml
• Addresses the currently reproducible dependency/runtime failure discussed in Dependencies Out of Date #316
• Addresses the same RequestsCookieJar runtime failure currently visible in the unit-test CI logs

Reproduction

With the current main dependency pin, examples/example.py fails after fetching Open-Meteo data:

NameError: name 'RequestsCookieJar' is not defined

The failure comes from requests-cache==1.2.0 serializing/deserializing cached responses with current transitive dependencies.

CI note

The currently failing visible unit-test check on this fork PR is a pull_request_target run that checks out upstream main, so it installs requests-cache==1.2.0 and reproduces the same RequestsCookieJar failure before this PR branch is actually tested. This PR addresses the underlying dependency/runtime failure; it does not change the workflow checkout behavior.

Verification

uv sync
.venv/bin/python examples/example.py
.venv/bin/python -m pytest tests/unit -q

Result:

examples/example.py -> [192 rows x 1 columns]
tests/unit -> 22 passed, 4 warnings

I also verified a clean installed-package path outside the source tree:

python3.11 -m venv /private/tmp/ocf-902-pr-venv
/private/tmp/ocf-902-pr-venv/bin/python -m pip install /path/to/Open-Source-Quartz-Solar-Forecast
/private/tmp/ocf-902-pr-venv/bin/python - <<'PY'
from datetime import datetime
from quartz_solar_forecast.forecast import run_forecast
from quartz_solar_forecast.pydantic_models import PVSite

site = PVSite(latitude=51.75, longitude=-1.25, capacity_kwp=1.25)
predictions_df = run_forecast(site=site, ts=datetime.today(), nwp_source="icon")
print(predictions_df.shape)
print(predictions_df["power_kw"].max())
PY

Result:

(192, 1)

[timothykou]

CI note: the visible failing branch_ci / test-unit (3.11) check appears to be from the pull_request_target workflow, and its log shows it checked out refs/remotes/origin/main at d9b3c95, not this PR branch. It also installed requests-cache==1.2.0, which this PR changes to 1.3.2, so that failing check is not exercising the branch change. The fork pull_request workflow is currently action_required, likely waiting for maintainer approval to run. Local verification from the PR body still applies.