Follow-up of T259890, the upstream issue was resolved. We can't use it yet, though, as we'll need phan 3.2.3 to be used in every branch where the phan job is active. However, since that's not going to happen soon, we might also add a hack to the phan script, detecting what version of phan is running, and choosing a color scheme consequently. Of note, the current implementation is using the PHAN_COLOR_SCHEME environment variable, but we can also use the --color-scheme argument.