OAPI: Clean up FlamencoVersion schema definition

Change the `FlamencoVersion` schema definition so that it follows the style
of the other schema definitions:

- List properties before mentioning which are required.
- Put quotes around the property names, so that they stand out from the
  other YAML keys.

pkg/api/flamenco-openapi.yaml

@@ -1066,10 +1066,10 @@ components:
   schemas:
     FlamencoVersion:
       type: object
-      required: [version, name]
       properties:
-        version: { type: string }
-        name: { type: string }
+        "version": { type: string }
+        "name": { type: string }
+      required: [version, name]
 
     ManagerConfiguration:
       type: object