fix: devbox-plugin.schema.json required properties (#2221)

The list had `readme` instead of `description`

## Summary

## How was it tested?

Signed-off-by: Saulo Vallory <[email protected]>

Author: svallory

.schema/devbox-plugin.schema.json

@@ -142,5 +142,5 @@
       }
     }
   },
-  "required": ["name", "version", "readme"]
+  "required": ["name", "version", "description"]
 }