Update fprime-system-reference to support building with fprime v3.4.0

[capsulecorplab]

Encountered the following CMake Error while attempting to run fprime-util generate with fprime v3.4.0

[capsulecorplab]

updated my environment to use python dependencies from fprime v3.4.0 here, but now I'm encountering a missing pkg-config tool CMake error when attempting to run fprime-util generate