Update compile_from_source.md

Add cuda12x to the list of targets

compile_from_source.md

 # Compiling from source
 
 Basic steps.
-1. `make [target]` where `[target]` is among `cuda92, cuda10x, cuda110, cuda11x, cpuonly`
+1. `make [target]` where `[target]` is among `cuda92, cuda10x, cuda110, cuda11x, cuda12x, cpuonly`
 2. `CUDA_VERSION=XXX python setup.py install`
 
 To run these steps you will need to have the nvcc compiler installed that comes with a CUDA installation. If you use anaconda (recommended) then you can figure out which version of CUDA you are using with PyTorch via the command `conda list | grep cudatoolkit`. Then you can install the nvcc compiler by downloading and installing the same CUDA version from the [CUDA toolkit archive](https://developer.nvidia.com/cuda-toolkit-archive).