George Vauter

Default value for allowed_sections causes TrestleError to be thrown

1

## Describe the bug Currently the allowed_section parameter passed to the assemble_profile_markdown method is being [initialized as an empty string](https://github.com/oscal-compass/compliance-trestle/blob/eb459a292abb7251ee6d321a81d46d041f2a9b0a/trestle/core/repository.py#L429). This is causing unwanted behavior in compliance-trestle's `ProfileAssemble` class which[...