[vsco] support '/video/' URLs (#4295 #6973)

requires yt-dlp/youtube-dl to handle m3u8 manifests

test/results/vsco.py

@@ -108,4 +108,24 @@ __tests__ = (
     "video": True,
 },
 
+{
+    "#url"     : "https://vsco.co/shavonec/video/c5eb34bb-dd13-4d7a-a09c-2a7cd719c9fa",
+    "#category": ("", "vsco", "video"),
+    "#class"   : vsco.VscoVideoExtractor,
+    "#pattern" : r"ytdl:https://stream\.mux\.com/3o01XbjqTI4rkeRwPzR17H9i7VSFdWX1h\.m3u8\?token=ey.+",
+
+    "date"       : "dt:2020-02-04 15:11:52",
+    "description": "Big news: 🎥 YOU CAN NOW POST VIDEOS TO VSCO ⚡️⚡️💪🏾. ⁣\n⁣\n🔗BTS from my #FashionIsActivism panel with the California African American Arts museum ✊🏾",
+    "extension"  : "mp4",
+    "filename"   : "3o01XbjqTI4rkeRwPzR17H9i7VSFdWX1h",
+    "grid"       : "",
+    "id"         : "c5eb34bb-dd13-4d7a-a09c-2a7cd719c9fa",
+    "meta"       : {},
+    "tags"       : [],
+    "user"       : "shavonec",
+    "video"      : True,
+    "width"      : 624,
+    "height"     : 1232,
+},
+
 )