Support multiple arguments for generate_model_yaml

[calight23]

The package currently supports multiple arguments for generate_source using dict syntax - would love to be able to do the same for generate_model_yaml!

Something like:

dbt run-operation generate_model_yaml --args '{"model_name": ["model_1","model_2"]}'

[angelica-lastra]

I'm going to work on a solution for this!