Add support for .pch headers

[pepicrft]

Resolves #5878

Short description 📝

This PR updates XcodeProj to 8.19.0, which includes .pch files as supported header files.

How to test the changes locally 🧐

You can add a .pch file as a header of a project.

Contributor checklist ✅

• The code has been linted using run mise run lint:fix
• The change is tested via unit testing or acceptance testing, or both
• The title of the PR is formulated in a way that is usable as a changelog entry
• In case the PR introduces changes that affect users, the documentation has been updated

Reviewer checklist ✅

• The code architecture and patterns are consistent with the rest of the codebase
• Reviewer has checked that, if needed, the PR includes the label changelog:added, changelog:fixed, or changelog:changed, and the title is usable as a changelog entry