Set C++ version to C++23 and minimum required cmake version to 3.28

- C++23 is ready enough and has a bunch of cool features:
  https://clang.llvm.org/cxx_status.html
- CMake 3.28 adds C++20 modules support:
  https://www.kitware.com/import-cmake-the-experiment-is-over/

Author: congard

CMakeLists.txt

@@ -1,7 +1,7 @@
-cmake_minimum_required(VERSION 3.18)
+cmake_minimum_required(VERSION 3.28)
 project(algine)
 
-set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD 23)
 
 message(VERBOSE "CMAKE_C_COMPILER: ${CMAKE_C_COMPILER}")
 message(VERBOSE "CMAKE_CXX_COMPILER: ${CMAKE_CXX_COMPILER}")

examples/CMakeLists.txt

@@ -1,7 +1,7 @@
-cmake_minimum_required(VERSION 3.18)
+cmake_minimum_required(VERSION 3.28)
 project(algine_examples)
 
-set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD 23)
 
 # silence warnings from sol2
 add_compile_options(-Wno-unknown-warning-option)

tests/CMakeLists.txt

@@ -1,7 +1,7 @@
-cmake_minimum_required(VERSION 3.10)
+cmake_minimum_required(VERSION 3.28)
 project(algine_tests)
 
-set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD 23)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 # silence warnings from sol2