[discovery] Relax _VALID_URL (Closes #8903)

youtube_dl/extractor/discovery.py

@@ -9,7 +9,7 @@ from ..compat import compat_str
 
 
 class DiscoveryIE(InfoExtractor):
-    _VALID_URL = r'''(?x)http://(?:www\.)?(?:
+    _VALID_URL = r'''(?x)https?://(?:www\.)?(?:
             discovery|
             investigationdiscovery|
             discoverylife|