[hbo] Add HBOEpisodeIE (#10892)

youtube_dl/extractor/extractors.py

@@ -348,7 +348,10 @@ from .goshgay import GoshgayIE
 from .gputechconf import GPUTechConfIE
 from .groupon import GrouponIE
 from .hark import HarkIE
-from .hbo import HBOIE
+from .hbo import (
+    HBOIE,
+    HBOEpisodeIE,
+)
 from .hearthisat import HearThisAtIE
 from .heise import HeiseIE
 from .hellporno import HellPornoIE