Update CMakeLists.txt

[michaeljyeates]

C++ std v20 is needed to compile

Change Description

Change CMAKE_CXX_STANDARD to 20 from 17, it uses std::span which gives this error when using v17

note: ‘std::span’ is only available from C++20 onwards
21 | inline thread_local std::spanstd::byte code_memory_range;

API Changes

• API Changes

Documentation Additions

• Documentation Additions

[spoonincode]

This change has already been made in main, as well as the commit of eos-vm that spring 1.1 is based on. Any reason you are targeting this change for spring 1.0 release branch version of eos-vm? As far as I know this c++17 vs c++20 setting doesn't affect building of spring. And I don't think we'd take a non-critical fix for 1.0.x now.