Using PY_VERSION_HEX to guard #error "PYTHON 2 IS NO LONGER SUPPORTED.

Author: rwgk

include/pybind11/detail/common.h

@@ -213,7 +213,7 @@
 
 
 #include <Python.h>
-#if PY_MAJOR_VERSION < 3
+#if PY_VERSION_HEX < 0x03000000
 #error "PYTHON 2 IS NO LONGER SUPPORTED. pybind11 v2.9.1 was the last to support Python 2."
 #endif
 #include <frameobject.h>