Warning about macro.cfg should be called before generate_openlane_files

[mbalestrini]

If you run --create-openlane-config without the instances info in macro.cfg you don't get to see the warning message about that file not being generated, because that call is after the process that throws the error (generate_openlane_files)

multi_project_tools/collect.py

Line 198 in ba52ec6

logging.warning("macros.cfg is not currently being automatically generated - please make sure this file is up to date")

[mbalestrini]

I created a PR