Add license metadata to pg19 (#4827)

* Add license metadata to pg19

* make it an array

Co-Authored-By: Roy Rijkers <royrijkers@live.nl>

Co-authored-by: Roy Rijkers <royrijkers@live.nl>

Commit from https://github.com/huggingface/datasets/commit/b5a455016043808e7b198117b344ba9f22265c2f

README.md

@@ -1,6 +1,8 @@
 ---
 language:
 - en
+license:
+- apache-2.0
 paperswithcode_id: pg-19
 pretty_name: PG-19
 ---
@@ -152,7 +154,7 @@ The data fields are the same among all splits.
 
 ### Licensing Information
 
-[More Information Needed](https://github.com/huggingface/datasets/blob/master/CONTRIBUTING.md#how-to-contribute-to-the-dataset-cards)
+Apache 2.0
 
 ### Citation Information