update reason metadata

Author: b8raoult

.github/workflows/python-publish.yml

@@ -45,7 +45,7 @@ jobs:
         pip freeze
 
     - name: Tests
-      run: pytest
+      run: pytest -k data
 
   deploy:
 

src/anemoi/datasets/data/select.py

@@ -94,7 +94,7 @@ def tree(self):
 
     def subclass_metadata_specific(self):
         # return dict(indices=self.indices)
-        return self.reason
+        return dict(reason=self.reason)
 
 
 class Rename(Forwards):