v0.6.0 dbt_salesforce_marketing_cloud

PR #19 includes the following updates:

Schema/Data Changes (--full-refresh required after upgrading)

1 total change • 1 possible breaking change

Data Model(s)	Change type	Old	New	Notes
All models	source_relation column (when using a single Salesforce Marketing Cloud schema)	Empty string ('')	<database>.<schema>

Feature Updates

• Introduces the new (recommended) salesforce_marketing_cloud_sources variable for more robust union data configuration. The old salesforce_marketing_cloud_union_schemas and salesforce_marketing_cloud_union_databases variables will still be supported. See the README for specific details.

Under the Hood

• Adds the fivetran_using_source_casing variable for case-sensitive destination support. When enabled, downstream transformations respect source casing to ensure consistent results. See the Additional Configurations section of the README for details.
• Introduces fivetran_utils.partition_by_source_relation to conditionally include source_relation in partition clauses only when multiple sources are configured.

Full Changelog: v0.5.1...v0.6.0