Add CI targets for updated Clang and MSVC compilers

[jbcoe]

GCC-15 runs do not work (yet). It looks like GCC-15 is not installed on the test runners.

[Twon]

Specifically, GCC-15 is not yet supported in the latest supported version of Ubuntu? Should we remove this until it's supported?

[jbcoe]

It's a reminder if left as is but we can do that with an issue. Probably best removed.

As you say, runners don't have the compiler version (yet).

[jbcoe]

I'll remove the comments and leave this PR open until CI passes.

[Copilot]

Pull Request Overview

This PR adds support for newer compiler versions to the CI matrix and cleans up the workflow configuration by removing a nonexistent file from the ignore list.

Key Changes

• Adds CI support for GCC-15, Clang-20, Visual Studio 2022 v20, and Apple Clang 16
• Removes requirements.txt from clang-tidy workflow's paths-ignore list (file doesn't exist in repository)

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
.github/workflows/cmake.yml	Adds four new compiler configurations to the build matrix: GCC-15, Clang-20, Visual Studio 2022 v20, and Apple Clang 16
.github/workflows/clang-tidy.yml	Removes nonexistent requirements.txt from paths-ignore lists in both push and pull_request triggers

[Copilot]

The std: 20 field is inconsistent with other Visual Studio entries (v16, v17, v18, v19) which don't include this field. For consistency with the existing pattern, either remove this field from the v20 entry or add it to all other Visual Studio entries. The field appears to not be used by the workflow steps, as the CMake configuration is handled by presets.

Suggested change

	compiler: { type: VISUAL, version: 20, cc: "cl", cxx: "cl", std: 20 },
	compiler: { type: VISUAL, version: 20, cc: "cl", cxx: "cl" },