Fix generated dbt project

  - use "ephemeral" instead of cte for materialization

The sample job in the suite at https://github.com/mildbyte/template-test-2/runs/4667663552?check_suite_focus=true
now actually completes (but doesn't do anything) because it just makes an unchecked
CTE (the source tables don't exist).

Fails as expected (https://github.com/mildbyte/template-test-2/runs/4667687824?check_suite_focus=true)
if we materialize as tables since then the relation indeed doesn't exist.

Author: mildbyte

splitgraph/cloud/project/templates.py

@@ -67,7 +67,7 @@
     # Here as a starting point. You can reference these models downstream in models that actually
     # materialize as tables.
     staging:
-      +materialized: cte
+      +materialized: ephemeral
 """
 
 SOURCES_YML_TEMPLATE = """# This file defines all data sources referenced by this model. The mapping

test/splitgraph/cloud/project/snapshots/test_dbt/test_generate_dbt_project/splitgraph_template/dbt_project.yml

@@ -30,4 +30,4 @@ models:
     # Here as a starting point. You can reference these models downstream in models that actually
     # materialize as tables.
     staging:
-      +materialized: cte
+      +materialized: ephemeral

test/splitgraph/cloud/project/snapshots/test_generation/test_generate_project_with_dbt/generate_project_dbt/dbt_project.yml

@@ -30,4 +30,4 @@ models:
     # Here as a starting point. You can reference these models downstream in models that actually
     # materialize as tables.
     staging:
-      +materialized: cte
+      +materialized: ephemeral