Update cmakefile for python alternative path

CMakeLists.txt

@@ -26,18 +26,22 @@ set(version 1.1.0)
 project(composable_kernel VERSION ${version} LANGUAGES CXX HIP)
 include(CTest)
 
+# Usage: for customized Python location cmake -DCK_USE_ALTERNATIVE_PYTHON="/opt/Python-3.8.13/bin/python3.8"
+# CK Codegen requires dataclass which is added in Python 3.7
+# Python version 3.8 is required for general good practice as it is default for Ubuntu 20.04
 if(NOT CK_USE_ALTERNATIVE_PYTHON)
-   find_package(Python3 3.6 COMPONENTS Interpreter REQUIRED)
+   find_package(Python3 3.8 COMPONENTS Interpreter REQUIRED)
 else()
    message("Using alternative python version")
    set(EXTRA_PYTHON_PATH)
+   # this is overly restrictive, we may need to be more flexible on the following
    string(REPLACE "/bin/python3.8" "" EXTRA_PYTHON_PATH "${CK_USE_ALTERNATIVE_PYTHON}")
    message("alternative python path is: ${EXTRA_PYTHON_PATH}")
-   find_package(Python3 3.6 COMPONENTS Interpreter REQUIRED)
    add_definitions(-DPython3_EXECUTABLE="${CK_USE_ALTERNATIVE_PYTHON}")
    set(Python3_EXECUTABLE "${CK_USE_ALTERNATIVE_PYTHON}")
    set(PYTHON_EXECUTABLE "${CK_USE_ALTERNATIVE_PYTHON}")
    set(ENV{LD_LIBRARY_PATH} "${EXTRA_PYTHON_PATH}/lib:$ENV{LD_LIBRARY_PATH}")
+   find_package(Python3 3.8 COMPONENTS Interpreter REQUIRED)
 endif()
 
 list(APPEND CMAKE_MODULE_PATH "${PROJECT_SOURCE_DIR}/cmake")