Fix rust issue running raylib on mac

instructions.md

Fix isue of raylib rust on mac

brew link --overwrite cmake

   Compiling raylib-sys v3.7.0
error: failed to run custom build command for `raylib-sys v3.7.0`

Caused by:
  process didn't exit successfully: `/Users/me/Code/rayrust/target/debug/build/raylib-sys-23c4441e62b28cda/build-script-build` (exit status: 101)
  --- stdout
  CMAKE_TOOLCHAIN_FILE_aarch64-apple-darwin = None
  CMAKE_TOOLCHAIN_FILE_aarch64_apple_darwin = None
  HOST_CMAKE_TOOLCHAIN_FILE = None
  CMAKE_TOOLCHAIN_FILE = None
  CMAKE_GENERATOR_aarch64-apple-darwin = None
  CMAKE_GENERATOR_aarch64_apple_darwin = None
  HOST_CMAKE_GENERATOR = None
  CMAKE_GENERATOR = None
  CMAKE_PREFIX_PATH_aarch64-apple-darwin = None
  CMAKE_PREFIX_PATH_aarch64_apple_darwin = None
  HOST_CMAKE_PREFIX_PATH = None
  CMAKE_PREFIX_PATH = None