can't pass --model-version via stage.py or mxbuild.py

[basi01]

We were calling mono mxbuild.exe directly and we were passing the argument --model-version= so the app knows its version.
Now we switched to the Python wrapper and I can't find a way to pass this argument. Here's how we build the .mda:

subprocess.check_call(["/opt/mendix/buildpack/buildpack/stage.py", BUILD_PATH, CACHE_PATH, DEPS_DIR, DEPS_IDX])

I searched for the string "model-version" in this repo and it's not here.
As a workaround we'll have to patch mxbuild.py on the fly.