Fix item.keys not list.

fetchYoutubeSubtitle.py

@@ -4,7 +4,7 @@ import yt_dlp
 
 def getVttUrlFromSubtitles(item, lang='en', vttType="vtt"):
     langs = item.keys()
-    key = lang if lang in langs else ('en' if 'en' in langs else langs[0] )
+    key = lang if lang in langs else ('en' if 'en' in langs else list(langs)[0] )
     for item in langs[key]:
         if(item.get("ext") == vttType):
             return item.get("url")