Add comment to connect with arXiv paper

Following the comment from https://discuss.huggingface.co/t/how-to-link-the-spaces-with-arxiv/27094/2?u=deepkyu, I add the HF model card link as a comment.

app.py

@@ -1,3 +1,4 @@
+# https://huggingface.co/deepkyu/ml-talking-face
 import os
 import subprocess