Outdated information on GPU support in Readme

[Menkalian]

The section on GPU compatibility in the Readme has not been updated after the recent addition of Apple silicon support.
Currently it is claiming only support for Linux with Nvidia/AMD/Intel.

README.md

285  ### **Optional Dependencies (Needed for GPU monitoring) (Only Linux)**
286  
287  GPU monitoring also requires a btop binary built with GPU support (`GPU_SUPPORT=true` flag).
288  
289  See [GPU compatibility](#gpu-compatibility) section for more about compiling with GPU support.
290  
291   * **NVIDIA**
292  
293     If you have an NVIDIA GPU you must use an official NVIDIA driver, both the closed-source and open-source ones have been verified to work.
294  
295     In addition to that you must also have the nvidia-ml dynamic library installed, which should be included with the driver package of your distribution.
296  
297   * **AMD**
298  
299     If you have an AMD GPU `rocm_smi_lib` is required, which may or may not be packaged for your distribution.
300  
301   * **INTEL**
302  
303     Requires a working C compiler if compiling from source.
304  
305     Also requires the user to have permission to read from SYSFS.
306  
307     Can be set with `make setcap` (preferred) or `make setuid` or by running btop with `sudo` or equivalent.
308  
309  ### **Notice (Text rendering issues)**

Also the macOS build instructions in the README do not document the new IOReport / Apple GPU build/link requirements nor the fact that GPU support is now enabled by default on macOS (Makefile now sets GPU_SUPPORT := true and ADDFLAGS adds -lIOReport). Following the existing README macOS compile steps (gmake / gmake install) may therefore fail at link time (missing IOReport library or incorrect link method) and the README does not tell users how to disable GPU support for macOS builds if necessary.

README.md, Line 636