Update README.md

When i was trying HfQueryAPI, I encounter this:

Initialized HfQueryAPI for BrentLab/hughes_2006
Repository type: dataset
Dataset card validation failed for BrentLab/hughes_2006:
- Field 'configs -> 1 -> applies_to': Input should be a valid list (got: metadata)
- Field 'configs -> 2 -> applies_to': Input should be a valid list (got: metadata)

so I think the file contains syntax errors. .

README.md

@@ -57,7 +57,8 @@ configs:
 - config_name: overexpression
   description: Overexpression perturbation normalized log2 fold changes
   dataset_type: annotated_features
-  applies_to: metadata
+  applies_to:
+  - metadata
   data_files:
   - split: train 
     path: overexpression.parquet
@@ -104,7 +105,8 @@ configs:
 - config_name: knockout
   description: Deletion/knockout perturbation normalized log2 fold changes
   dataset_type: annotated_features
-  applies_to: metadata
+  applies_to:
+  - metadata
   data_files:
   - split: train
     path: knockout.parquet