…s to set version
Advantages:
- not modifying src dir in build time (`git clean` will also remove
less)
- simpler codecov (if we decide to move it to separate stage in the
future)
- The cpp file is perfectly valid, so it will be treated as a C++ files
by all the tooling
- No need to use CMAKE_PROJECT_INCLUDE_BEFORE, should work fine without
it
- Instead of generating + recompiling, we will just be doing
recompilation of 1 file