[CT-3147] [Implementation] update config block names for data tests and unit tests

[graciegoheen]

Housekeeping

• I am a maintainer of dbt-core

Short description

From #8606

We should updating the config names

• from unit: -> unit-tests:
• and tests: -> data-tests: (we should preserve tests: for backwards compatibility)

In dbt_project.yml:

data-tests:
...
unit-tests:

as well as in schema yml files:

models:
  - name: orders
    columns:
      - name: order_id
        data_tests:
          - unique
          - not_null

Acceptance criteria

• config name for unit tests is unit-tests:
• config name for data tests is data-tests: or tests: (the latter for backwards compatibility)
• deprecation warning for tests:

Impact to Other Teams

None

Will backports be required?

None

Context

No response

[graciegoheen]

Notes from refinement:

• what happens if someone passes in both tests: and data-tests:? we will not support both
• deprecation warning for tests:

[emmyoop]

unit-tests was converted in #8988

[emmyoop]

This was completed by #9201