[release/3.0] Pin Microsoft.Internal.Extensions.Refs (#15062)
[release/3.0] Pin Microsoft.Internal.Extensions.Refs (#15062)

* Pin Microsoft.Internal.Extensions.Refs
This is not being produced in current 3.0 builds so the coherent parent dependency attribute cannot be satisfied.
aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore