Update nlohmann_json package

[meator]

This PR fixes the following configure error when using nlohmann_json provided by CMake:

CMake Error at /tmp/linuxdeploy-plugin-qt-build-plmioK/_deps/nlohmann_json-src/CMakeLists.txt:1 (cmake_minimum_required):
  Compatibility with CMake < 3.5 has been removed from CMake.

  Update the VERSION argument <min> value.  Or, use the <min>...<max> syntax
  to tell CMake that the project requires at least <min> but has been updated
  to work with policies introduced by <max> or earlier.

  Or, add -DCMAKE_POLICY_VERSION_MINIMUM=3.5 to try configuring anyway.

[TheAssassin]

Thanks! If CI agrees, let's merge this.