fix: update the mock API

Signed-off-by: Rustin170506 <[email protected]>

Author: 0xPoe

mirage/route-handlers/crates.js

@@ -271,6 +271,11 @@ export function register(server) {
       return notFound();
     }
 
+    const version = schema.versions.findBy({ crateId: crate.id, num: versionNum });
+    if (!version) {
+      return notFound();
+    }
+
     return {};
   });