Support for gfycat urls redirecting to gifdeliverynetwork

[parasiteoflife]

Checklist

• I'm reporting a broken site support
• I've verified that I'm running youtube-dl version 2020.06.16.1
• I've checked that all provided URLs are alive and playable in a browser
• I've checked that all URLs and arguments with special characters are properly quoted or escaped
• I've searched the bugtracker for similar issues including closed ones

Verbose log

[debug] System config: []
[debug] User config: []
[debug] Custom config: []
[debug] Command-line args: ['-v', '--newline', '-i', '-o', 'Z:\\gif.%(ext)s', 'https://gfycat.com/ColossalFaithfulAsiaticlesserfreshwaterclam']
[debug] Encodings: locale cp1252, fs mbcs, out cp850, pref cp1252
[debug] youtube-dl version 2020.06.16.1
[debug] Python version 3.4.4 (CPython) - Windows-10-10.0.18362
[debug] exe versions: ffmpeg git-2020-06-19-2f59946, ffprobe git-2020-06-19-2f59946
[debug] Proxy map: {}
[Gfycat] ColossalFaithfulAsiaticlesserfreshwaterclam: Downloading video info
ERROR: Unable to download JSON metadata: HTTP Error 404: Not Found (caused by HTTPError()); please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; type  youtube-dl -U  to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\extractor\common.py", line 627, in _request_webpage
  File "C:\Users\dst\AppData\Roaming\Build archive\youtube-dl\ytdl-org\tmpspbsbtmq\build\youtube_dl\YoutubeDL.py", line 2238, in urlopen
  File "C:\Python\Python34\lib\urllib\request.py", line 470, in open
  File "C:\Python\Python34\lib\urllib\request.py", line 580, in http_response
  File "C:\Python\Python34\lib\urllib\request.py", line 508, in error
  File "C:\Python\Python34\lib\urllib\request.py", line 442, in _call_chain
  File "C:\Python\Python34\lib\urllib\request.py", line 588, in http_error_default

Description

Some gfycat urls now redirect to contentdeliverynetwork.com, so with the above used url the website redirects from https://gfycat.com/ColossalFaithfulAsiaticlesserfreshwaterclam to https://www.gifdeliverynetwork.com/colossalfaithfulasiaticlesserfreshwaterclam which ytdl fails to recognize.
Please add support for them.