message: Bumping version to 1.13.0
diff: #pragma once
  #define ISPC_VERSION_MAJOR 1
  -#define ISPC_VERSION_MINOR 12
  -#define ISPC_VERSION "1.12.1dev"
  +#define ISPC_VERSION_MINOR 13
  +#define ISPC_VERSION "1.13.0"
  #include "llvm/Config/llvm-config.h"
  #define ISPC_LLVM_VERSION (LLVM_VERSION_MAJOR * 10000 + LLVM_VERSION_MINOR * 100)
  