docs(storage): updating the encryption key GCS sample (#28815)

Author: shubhangi-google

google-cloud-storage/samples/storage_upload_encrypted_file.rb

@@ -23,8 +23,10 @@ def upload_encrypted_file bucket_name:, local_file_path:, file_name: nil, encryp
   # The ID of your GCS object
   # file_name = "your-file-name"
 
-  # The key to encrypt the object with
-  # encryption_key = "TIbv/fjexq+VmtXzAlc63J4z5kFmWJ6NdAPQulQBT7g="
+  # The encryption key used for securing the object must be a 32-byte key consisting of raw encrypted data.
+  # Key used should not be base64 encoded.
+
+  # encryption_key = "your-encryption-key"
 
   require "google/cloud/storage"