Allowing manufacturer urls to be null

app/crud/manufacturer.py

@@ -26,7 +26,7 @@ async def create(
     db: AsyncSession,
     *,
     name: str,
-    url: str,
+    url: str | None = None,
     logo_url: str | None = None,
 ) -> Manufacturer:
     m = Manufacturer(name=name, url=url, logo_url=logo_url)