Minor fix for 6.2.0
Fix a mistake in the v6.2.0 release, which installed projects using @angular-devkit/*@~0.8.0-rc.0
These should not have pointed to an RC. Now we use @angular-devkit/*@~0.8.0
Note this makes no observable difference, since the final RC was identical to the 0.8.0 release of these packages.