Added Clang compiler configuration to the Windows CI workflow.

[Keerthi421]

This PR addresses [issue #479 ] by adding a Clang compiler configuration to the Windows CI workflow.

Changes Made: -->Added a new build configuration (build: 11) to the Windows matrix in .github/workflows/ci_workflow.yml -->Created a corresponding install manifest file at share/ci/install_manifest/install_manifest.windows.11.txt for validation purposes

Rationale: -->This addition ensures Clang is used in Windows CI builds, mirroring the approach already implemented for Linux (e.g., build: 6). Specifically: -->The CI job sets both C and C++ compiler environment variables to use Clang --> dedicated manifest file ensures the validation script can verify the build's correctness

Why This Matters : By integrating Clang into the Windows CI pipeline, the Imath library can be tested more broadly across different compilers and platforms. This improves the robustness and portability of the codebase and aligns with the project's goal of supporting cross-platform compatibility.

[linux-foundation-easycla[bot]]

• :x: - login: @Keerthi421 / name: Keerthi . The commit (87a3bd2fda4452b37dc038958834bc84c7183401) is not authorized under a signed CLA. Please click here to be authorized. For further assistance with EasyCLA, please submit a support request ticket.

[cary-ilm]

Also, our project policy is to require a signed Contributor License Agreement, so could you click the red NOT COVERED button next to EasyCLA above and sign the paperwork?

We also require a Digital Certificate of Origin (DCO), which means that commits need to be signed by using the -s option. You can fix this by running git commit -s --amend --no-edit. This adds the "Signed-off-by" line to the commit message. Note that all commits need to be signed, so you'll need to sign this original commit and re-push it before proceeding with the fixes requested above.

Thanks again for the contribution!

[cary-ilm]

Checking back on this, would you be able to complete this? Note that come changes have gone in since, so you'll need to rebase off of the main branch, and the install manifest may have changed.

[cary-ilm]

Closing for now due to inactivity, feel free to re-open or re-submit.