I ran into the same problem and solved it by following the instructions here. This link describes a similar, but slightly different installer issue.
To summarize, you need to ensure that the Xcode command line tools are installed and set up correctly. I already had them installed, but had to go into Preferences -> Locations in Xcode and set the dropdown to the currently installed version.
The link shows an earlier version of Xcode where the path is actually Preferences -> Downloads -> Components.
Once I’d made this change, the installer continued successfully.