qt5-qtwebengine on macOS 10.13, Xcode version

[Ryan Schmidt]

On Dec 27, 2020, at 10:11, Ken Cunningham wrote:

> However, I would float the idea it's time the buildbot and all 10.13 users moved to Xcode 10.
> 
> Xcode 10's issues have largely been worked around by this point it seems, although there a couple of stragglers still.

I intentionally keep most of the buildbot workers' Xcode versions at the last version that contains the SDK that matches the OS version. On macOS 10.13, that's Xcode 9.4.1.