message: Add version and license to meson.build
diff: -project('nlohmann_json', 'cpp')
  +project('nlohmann_json',
  + 'cpp',
  + version : '3.2.0',
  + license : 'MIT',
  +)
  nlohmann_json_dep = declare_dependency(
  include_directories: include_directories('single_include')
  