update readme with option examples

README.md

@@ -66,6 +66,9 @@ $ youtube-upload \
   --description="A.S. Mutter plays Beethoven" \
   --category=Music \
   --tags="mutter, beethoven" \
+  --recording-date="2011-03-10T15:32:17.0Z" \
+  --default-language="en" \
+  --default-audio-language="en" \
   --client-secrets=my_client_secrets.json \
   --credentials-file=my_credentials.json \
   --playlist "My favorite music" \