Move dbt package release notes to separate group at bottom

- Moved release notes from nested group to separate group at bottom
- Keeps release notes visible but separate from main package docs

Author: NoyaOffer

docs/docs.json

@@ -303,6 +303,21 @@
               "data-tests/dbt/package-models"
             ]
           },
+          {
+            "group": "dbt Package Release Notes",
+            "pages": [
+              "data-tests/dbt/release-notes/releases/0.20.1",
+              "data-tests/dbt/release-notes/releases/0.20.0",
+              "data-tests/dbt/release-notes/releases/0.19.4",
+              "data-tests/dbt/release-notes/releases/0.19.3",
+              "data-tests/dbt/release-notes/releases/0.19.2",
+              "data-tests/dbt/release-notes/releases/0.19.1",
+              "data-tests/dbt/release-notes/releases/0.19.0",
+              "data-tests/dbt/release-notes/releases/0.18.3",
+              "data-tests/dbt/release-notes/releases/0.18.2",
+              "data-tests/dbt/release-notes/releases/0.18.1"
+            ]
+          },
           {
             "group": "Elementary Data tests",
             "pages": [