change main C++ standard to C++20

CMakeLists.txt

@@ -9,6 +9,6 @@ add_subdirectory(td)
 
 add_executable(${PROJECT_NAME} main.cpp config.cpp http.cpp manager.cpp posts.cpp state.cpp tg.cpp vk.cpp)
 
-target_compile_options(${PROJECT_NAME} PRIVATE -std=c++2b)
+target_compile_options(${PROJECT_NAME} PRIVATE -std=c++2a)
 
 target_link_libraries(${PROJECT_NAME} PRIVATE CURL::libcurl nlohmann_json::nlohmann_json uv spdlog::spdlog Td::TdStatic $<$<BOOL:${MINGW}>:ws2_32>)