os/mac/xcode: support Xcode 11.4.1

[Bo98]

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew style with your changes locally?
• Have you successfully run brew tests with your changes locally?

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Note: There is a CLT 11.4.1 available, and it was offered through softwareupdate on the CI VMs. As per previous discussion, I have not touched latest_clang_version here however.

For future reference, the new Clang version is 1103.0.32.59.

[MikeMcQuaid]

As per previous discussion, I have not touched latest_clang_version here however.

I think now we've updated the instructions to be more reliable (and I can confirm I did receive this update through softwareupdate already) that it's actually fine to bump the clang_version. Sorry ❤️

[Bo98]

Good to hear you got the update too!

[MikeMcQuaid]

Thanks again @Bo98!