Update optuna requirement from >=3.0 to >=4.8.0

[dependabot]

Updates the requirements on optuna to permit the latest version.

Release notes

Sourced from optuna's releases.

v4.8.0

This is the release note of v4.8.0.

Highlights

Support for Constant Liar Strategy to GPSampler

A constant liar strategy for efficient parallelization has been introduced to GPSampler by @​sawa3030. The figures (left: v4.7.0, right: v4.8.0) show that the overlap of search points has decreased, and a wider variety of solutions are being explored. The experiment uses n_jobs = 10 and n_trials = 100. Currently, this feature supports single-objective and unconstrained optimization. Further extensions are coming in v4.9.0.

v4.7.0	v4.8.0

SHAP-like beeswarm plot visualization

@​yasumorishima introduces the new visualization to OptunaHub. Please refer to https://hub.optuna.org/visualization/plot_beeswarm/ for details.

New Features

• Add Trackio Integration for Optuna (optuna/optuna-integration#259, thanks @​ParagEkbote!)
• Add constant liar strategy to GPSampler (#6430)

Enhancements

• Validate artifact_id in FileSystemArtifactStore to prevent path traversal (#6432, thanks @​RinZ27!)
• fix: correct inverted warning message in pareto front plot (#6498, thanks @​aerosta!)

Bug Fixes

• Fix shared callback state in parallel OptunaSearchCV with LightGBM (optuna/optuna-integration#260, thanks @​Quant-Quasar!)
• Fix GPSampler crash when torch default device is CUDA (#6418, thanks @​VedantMadane!)
• Fix combination between PartialFixedSampler and TPESampler with group decomposed search space (#6428)
• Fix TPESampler with multivariate and constant_liar (#6505)

Documentation

• Add documentation indicating that WilcoxonPruner requires scipy (#6477)
• Remove version & language selectors in the sidebar of docs (#6482)

Examples

• Apply black 26.1.0 (optuna/optuna-examples#348)
• Remove CI workflow for allennlp since no longer maintained (optuna/optuna-examples#351)
• Reduce the frequency of scheduled CI triggers (optuna/optuna-examples#352)
• Remove the scheduled trigger for aim CI (optuna/optuna-examples#353)
• Add constraint to transformers (optuna/optuna-examples#355)

Tests

... (truncated)

Commits

• 689c62d Merge pull request #6509 from y0z/feature/bump-up-release480
• 9e2e065 Bump up version
• 54fe633 Merge pull request #6507 from sateeshkumarb/master
• 8efb8b4 Move imports used for typecheck under TYPE_CHCKING
• c0fcd2e Merge pull request #6506 from acabellom/fix-fstring-file
• 087cc9d Replace .format() with f-strings in 002_configurations.py
• 274f5b9 Merge pull request #6505 from not522/fix-multivariate-constant_liar
• ce882f6 Revert "Merge pull request #6265 from not522/relative-use-cache"
• f9e546d Merge pull request #6498 from aerosta/fix/pareto-front-warning-message
• 535215b Merge pull request #6502 from nightcityblade/fix/issue-6029-patient-pruner
• Additional commits viewable in compare view