add the option to the schema

src/changelog-schema.js

@@ -50,6 +50,11 @@ export default {
         with_stats: {
           description: "if true, add git statistics when bumping the version.",
         },
+        next_directory: {
+          type: "string",
+          description:
+            "directory where the changes for the NEXT release are stashed",
+        },
       },
       type: "object",
     },