Files under ArmTemplates are manually generated by command
for f in Bicep/*.bicep; do az bicep build -f "$f" --outdir ArmTemplates; done
So do the generation whenever there's an update to the source files in Bicep and commit the changes of ArmTemplates to Git.
TODO: Autogeneration in compile time would be great. Then ArmTemplates would not be needed in source code, but it's still required in the runtime.