create_adpater_plugin bug with --dependency flag

[scarrucciu]

Describe the bug

Bug in create_adapter_plugin.py script when a dependency is not passed in via the --dependency arg.

Steps To Reproduce

Run the create_adapter_plugin.py script without a --dependency arg. The variable 'prefix' is not defined in the else condition.

Expected behavior

The script should trigger the else condition.

Screenshots and log output

System information

Which database are you using dbt with?

• postgres
• redshift
• bigquery
• snowflake
• other (specify: ____________)

The output of dbt --version:

Newest release candidate

The operating system you're using:

The output of python --version:

Additional context