Update README.md

[SuperSecureHuman]

When using Cuda 11.6, NVCC expects the compiler version to be less than 11.x.x. (For diffvg)

Updated a solution on the readme

[ximinng]

I used CUDA version 11.7 and did not find this issue, I kept the issue open to see if I encountered the same thing

[SuperSecureHuman]

Makes sense. It dosent come up when the GCC version 11 or lower. In my case, when I was using it locally, I got the issue. My local GCC is version 13.x.x.

[ximinng]

My GPU server GCC version is 12.1.0.
Anyway, thanks for asking this question, I think it's helpful for other players!