Bump Roslyn dependency to 2.8.0
Bump Roslyn dependency to 2.8.0

(cherry picked from commit a8e1a1fd40a34fc80cd805a38effed28a81adb9d)

aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore,aspnet/AspNetCore