Update default cuda architecture.
- Cuda 11 dropped support for -arch=sm_30. The default was therefore updated to compute_53 when cuda 11 is found.
- Furthermore, it was impossible to select virtual architectures such as compute_70,
since sm_ is always prepended to the CMake variable.
Now, one specifies
-DCUDA_ARCH=sm_35
instead of-DCUDA_ARCH=35