Update sdk to 7.0.100-alpha.1.21470.6 (#36781)
Update sdk to 7.0.100-alpha.1.21470.6 (#36781)

- getting closer to undoing our `net6.0` hold backs but aren't there yet&hellip;

Co-authored-by: Doug Bunting <79e38e53333d721588110d2ac143e11f37bec7f9@users.noreply.github.com>
aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore