Write current epoch to infojson when using `--no-clean-infojson`

Closes #191

yt_dlp/YoutubeDL.py

@@ -2539,6 +2539,7 @@ class YoutubeDL(object):
     @staticmethod
     def filter_requested_info(info_dict, actually_filter=True):
         if not actually_filter:
+            info_dict['epoch'] = int(time.time())
             return info_dict
         exceptions = {
             'remove': ['requested_formats', 'requested_subtitles', 'filepath', 'entries'],

yt_dlp/extractor/youtube.py

@@ -2150,7 +2150,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
                 # This will error if there is no livechat
                 initial_data['contents']['twoColumnWatchNextResults']['conversationBar']['liveChatRenderer']['continuations'][0]['reloadContinuationData']['continuation']
                 info['subtitles']['live_chat'] = [{
-                    'url': 'https://www.youtube.com/watch?v=%s' % video_id, # url is needed to set cookies
+                    'url': 'https://www.youtube.com/watch?v=%s' % video_id,  # url is needed to set cookies
                     'video_id': video_id,
                     'ext': 'json',
                     'protocol': 'youtube_live_chat_replay',