Migrate to using Mergeable from `dbt-common

[QMalcolm]

Housekeeping

• I am a maintainer of dbt-core

Short description

We're currently in the process of moving the "data resource" portion on nodes to dbt/artifacts. Some of those artifacts depend on Mergeable which has been defined on core. In order to move the data resources to dbt/artifacts, we thus need to move Mergeable upstream of core. We moved Mergeable to dbt-common in dbt-labs/dbt-common#59, and released this change in dbt-common 0.1.3. As such as, in order to unblock some of the dbt/artifacts migration work, we first need to update references to Mergeable in core to use the dbt-common definition.

Acceptance criteria

All uses of Mergeable in core use the definition in dbt-common

Suggested Tests

None

Impact to Other Teams

None

Will backports be required?

No

Context

No response