add model vars json to packagE

Author: jdebacker

setup.py

@@ -18,7 +18,7 @@
     },
     packages=["ogcore"],
     package_data={
-        "ogcore": ["default_parameters.json", "OGcorePlots.mplstyle"]
+        "ogcore": ["default_parameters.json", "model_variables.json", "OGcorePlots.mplstyle"]
     },
     include_packages=True,
     python_requires=">=3.7.7, <3.13",