Issue might be that I'm unable to install SDK listed in `global.json` (`6.0.100-rc.1.21411.28`) and replacing it with `6.0.100-preview.7.21379.14` didn't quite work.    Could you help me with installing `6.0.100-rc.1.21411.28` or reconfiguring it to use `6.0.100-preview.7.21379.14`?