Update to clang 20.1.8

[bdice]

Description

Contributes to rapidsai/build-planning#267

This PR updates the clang version to 20.1.8.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

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Review profile: CHILL

Plan: Pro

Run ID: b7301c02-2b03-4d65-82c7-55e4a031421d

📥 Commits

Reviewing files that changed from the base of the PR and between 4091267 and 6718180.

📒 Files selected for processing (6)

• .pre-commit-config.yaml
• BUILD.md
• conda/environments/clang_tidy_cuda-129_arch-x86_64.yaml
• conda/environments/clang_tidy_cuda-131_arch-x86_64.yaml
• cpp/README.md
• dependencies.yaml

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📝 Walkthrough

Summary by CodeRabbit

• Chores

  • Updated Clang/LLVM toolchain dependencies from version 20.1.4 to 20.1.8, including clang, clang-tools, and llvm-openmp packages across all development environments, build configurations, and pre-commit hooks.

• Documentation

  • Updated clang-format version requirement documentation to reflect the upgraded toolchain version.

Walkthrough

The pull request updates the Clang/LLVM toolchain version from 20.1.4 to 20.1.8 across pre-commit configuration, build documentation, conda environment files, C++ README, and dependency management files.

Changes

Cohort / File(s)	Summary
Pre-commit Configuration .pre-commit-config.yaml	Updated pre-commit/mirrors-clang-format hook revision from v20.1.4 to v20.1.8.
Documentation BUILD.md, cpp/README.md	Updated documented clang-format version requirement from 20.1.4 to 20.1.8.
Conda Environments conda/environments/clang_tidy_cuda-129_arch-x86_64.yaml, conda/environments/clang_tidy_cuda-131_arch-x86_64.yaml	Updated LLVM/Clang toolchain components (clang, clang-tools, llvm-openmp) from 20.1.4 to 20.1.8.
Dependency Management dependencies.yaml	Updated clang_tidy.common.packages dependency pins for clang, clang-tools, and llvm-openmp from 20.1.4 to 20.1.8.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

🚥 Pre-merge checks | ✅ 3

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title 'Update to clang 20.1.8' is directly related to the main change in the changeset, which updates clang/LLVM components across multiple configuration files from version 20.1.4 to 20.1.8.
Description check	✅ Passed	The description clearly states the purpose of the PR: updating clang version to 20.1.8, which directly relates to the comprehensive version updates shown across all modified files.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[bdice]

/merge