[20min] Fix embeds extraction

youtube_dl/extractor/twentymin.py

@@ -50,7 +50,7 @@ class TwentyMinutenIE(InfoExtractor):
     @staticmethod
     def _extract_urls(webpage):
         return [m.group('url') for m in re.finditer(
-            r'<iframe[^>]+src=(["\'])(?P<url>(?:https?://)?(?:www\.)?20min\.ch/videoplayer/videoplayer.html\?.*?\bvideoId@\d+.*?)\1',
+            r'<iframe[^>]+src=(["\'])(?P<url>(?:(?:https?:)?//)?(?:www\.)?20min\.ch/videoplayer/videoplayer.html\?.*?\bvideoId@\d+.*?)\1',
             webpage)]
 
     def _real_extract(self, url):