updated license information

Creating PR to update license info as part of #hectoberfest challenge, please kindly review.

README.md

@@ -7,6 +7,9 @@ datasets:
 language:
 - en
 pipeline_tag: text-generation
+license: other
+license_name: stable-beluga
+license_url: https://huggingface.co/stabilityai/StableBeluga2/blob/main/LICENSE.txt
 ---
 # Stable Beluga 2