Update post-hook for "latest" model version (#3652)

This is still just a placeholder "YMMV" solution until we decide on a
real implementation:
- dbt-labs/dbt-core#7442

---

If you're versioning `some_model` for the first time:
- that model is materialized as a `table`
- `my_db.my_schema.some_model` will exist as a table in the database
- needs to be dropped before running `create or replace view`

(NOTE: I need to actually test this code)

Co-authored-by: Joel Labes <[email protected]>

website/docs/docs/collaborate/govern/model-versions.md

@@ -326,7 +326,13 @@ We intend to build this into `dbt-core` as out-of-the-box functionality. (Upvote
     -- otherwise, it's a no-op
     {% if model.get('version') and model.get('version') == model.get('latest_version') %}
 
-        {% set new_relation = this.incorporate(path={"identifier": model['name']}) %}  
+        {% set new_relation = this.incorporate(path={"identifier": model['name']}) %}
+
+        {% set existing_relation = load_relation(new_relation) %}
+
+        {% if existing_relation and not existing_relation.is_view %}
+            {{ drop_relation_if_exists(existing_relation) }}
+        {% endif %}
         
         {% set create_view_sql -%}
             -- this syntax may vary by data platform