fix outdated comment

Author: Ian-Nara

examples/sample_encryption.py

@@ -5,7 +5,7 @@
 from uid2_client import encrypt_data, decrypt_data
 
 # THIS FILE IS DEPRECATED!
-# To learn how to encrypt and decrypt a UID2 advertising token, see sample_client.py.
+# To learn how to encrypt and decrypt a UID2 advertising token, see sample_sharing.py (For sharers. See sample_client.py for DSPs)
 
 def _usage():
     print('Usage: python3 sample_encryption.py <base_url> <auth_key> <secret_key> <ad_token> <data>', file=sys.stderr)