Use Version 2 config for sqlc.yaml (#3861)

This makes it easier to reuse examples from the documentation.

sqlc.yaml

@@ -13,19 +13,21 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-version: "1"
-packages:
-  - name: "db"
-    path: "./internal/db/"
+version: "2"
+sql:
+  - schema: "./database/migrations/"
     queries: "./database/query/"
-    schema: "./database/migrations/"
     engine: "postgresql"
-    emit_json_tags: true
-    emit_prepared_queries: false
-    emit_interface: true
-    emit_exact_table_names: false
-    emit_empty_slices: true
-    overrides:
-      - db_type: profile_selector
-        go_type:
-          type: "ProfileSelector"
+    gen:
+      go:
+        out: "./internal/db/"
+        package: "db"
+        emit_json_tags: true
+        emit_prepared_queries: false
+        emit_interface: true
+        emit_exact_table_names: false
+        emit_empty_slices: true
+        overrides:
+          - db_type: profile_selector
+            go_type:
+              type: "ProfileSelector"